Update crates versions (especially, git2)

[igxactly]

I had problem installing cargo-update using "cargo install cargo-update" with aarch64-darwin rust toochain setup.

It seems there has been some issues about finding and including/linking iconv library resources, when there is libiconv installed through macports.

• Build fails on macOS Sierra (10.12.6) due to undefined symbols rust-lang/git2-rs#263
• could not compile cargo-generate cargo-generate/cargo-generate#341 (comment)

I tried to update git2-rs and some other packages that does not break build and test, and it worked. (Though there was some comment of someone who solved problem by deactivating macports libiconv. I did not deactivate it, and did update cargo.toml )

[nabijaczleweli]

I don't see how this is compatible with the 1.35.0 compatibility guarantee?

    Updating crates.io index
   Compiling libc v0.2.101
   Compiling autocfg v1.0.1
   Compiling pkg-config v0.3.19
   Compiling proc-macro2 v1.0.29
   Compiling tinyvec_macros v0.1.0
   Compiling matches v0.1.9
   Compiling memchr v2.4.1
   Compiling unicode-xid v0.2.2
   Compiling percent-encoding v2.1.0
   Compiling syn v1.0.75
   Compiling log v0.4.14
   Compiling bitflags v1.2.1
   Compiling serde v1.0.130
   Compiling serde_derive v1.0.130
   Compiling unicode-width v0.1.8
   Compiling cfg-if v1.0.0
   Compiling regex-syntax v0.6.25
   Compiling semver-parser v0.7.0
   Compiling ansi_term v0.11.0
   Compiling openssl-probe v0.1.4
   Compiling strsim v0.8.0
   Compiling vec_map v0.8.2
   Compiling json v0.12.4
   Compiling array_tool v1.0.3
   Compiling lazy_static v1.4.0
   Compiling hex v0.4.3
   Compiling lazysort v0.2.1
   Compiling unicode-bidi v0.3.5
error[E0658]: use of unstable library feature 'maybe_uninit' (see issue #53491)
  --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/json-0.12.4/src/util/print_dec.rs:63:19
   |
63 |     let mut buf = mem::MaybeUninit::<[u8; BUF_LEN]>::uninit();
   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: use of unstable library feature 'alloc': this library is unlikely to be stabilized in its current form or name (see issue #27783)
  --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/hex-0.4.3/src/lib.rs:41:1
   |
41 | extern crate alloc;
   | ^^^^^^^^^^^^^^^^^^^

error[E0658]: use of unstable library feature 'iter_copied' (see issue #57127)
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/json-0.12.4/src/parser.rs:464:71
    |
464 |                     [codepoint, self.read_hexdec_codepoint()?].iter().copied()
    |                                                                       ^^^^^^

   Compiling tinyvec v1.3.1
   Compiling tabwriter v1.2.1
   Compiling form_urlencoded v1.0.1
error[E0658]: use of unstable library feature 'maybe_uninit' (see issue #53491)
  --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/json-0.12.4/src/util/print_dec.rs:65:23
   |
65 |     let buf_ptr = buf.as_mut_ptr() as *mut u8;
   |                       ^^^^^^^^^^

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0658`.
error: Could not compile `json`.
warning: build failed, waiting for other jobs to finish...
error[E0658]: naming constants with `_` is unstable (see issue #54912)
  --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/memchr-2.4.1/src/memmem/prefilter/fallback.rs:37:1
   |
37 | const _: PrefilterFnTy = find;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: naming constants with `_` is unstable (see issue #54912)
 --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/memchr-2.4.1/src/memmem/prefilter/x86/avx.rs:9:1
  |
9 | const _: PrefilterFnTy = find;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: naming constants with `_` is unstable (see issue #54912)
 --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/memchr-2.4.1/src/memmem/prefilter/x86/sse.rs:9:1
  |
9 | const _: PrefilterFnTy = find;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: non exhaustive is an experimental feature (see issue #44109)
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/memchr-2.4.1/src/memmem/prefilter/mod.rs:152:1
    |
152 | #[non_exhaustive]
    | ^^^^^^^^^^^^^^^^^

error[E0658]: use of unstable library feature 'alloc': this library is unlikely to be stabilized in its current form or name (see issue #27783)
  --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/tinyvec-1.3.1/src/lib.rs:88:1
   |
88 | pub extern crate alloc;
   | ^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0658`.
error: Could not compile `hex`.
warning: build failed, waiting for other jobs to finish...
error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0658`.
error: Could not compile `memchr`.
warning: build failed, waiting for other jobs to finish...
error: enum variants on type aliases are experimental
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/tinyvec-1.3.1/src/tinyvec.rs:110:7
    |
110 |       Self::Heap(v) => Self::Heap(v.clone()),
    |       ^^^^^^^^^^^^^

error: enum variants on type aliases are experimental
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/tinyvec-1.3.1/src/tinyvec.rs:111:7
    |
111 |       Self::Inline(v) => Self::Inline(v.clone()),
    |       ^^^^^^^^^^^^^^^

error: enum variants on type aliases are experimental
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/tinyvec-1.3.1/src/tinyvec.rs:110:24
    |
110 |       Self::Heap(v) => Self::Heap(v.clone()),
    |                        ^^^^^^^^^^

error: enum variants on type aliases are experimental
   --> /home/nabijaczleweli/.cargo/registry/src/github.com-1ecc6299db9ec823/tinyvec-1.3.1/src/tinyvec.rs:111:26
    |
111 |       Self::Inline(v) => Self::Inline(v.clone()),
    |                          ^^^^^^^^^^^^

error: aborting due to 5 previous errors

For more information about this error, try `rustc --explain E0658`.
error: Could not compile `tinyvec`.
warning: build failed, waiting for other jobs to finish...
error: build failed

This looks like you have a broken system more than anything wrong with end-user applications?

[igxactly]

@nabijaczleweli Sorry, my PR was too naive. I didn't consider about older version compatibility.