Bump version, MSRV and update coverage CI.

I don't like it, but this
post (https://users.rust-lang.org/t/rust-version-requirement-change-as-semver-breaking-or-not/20980/65)
suggests that it's fine to release a patch version from 0.x.y to
0.x.(y+1) when bumping the MSRV. I wouldn't normally do this, but it's
unlikely to affect anyone, and we're doing it because someone else
bumped MSRV when they probably shouldn't have. /shrug

mwalib's CI was still using the nightly toolchain to generate coverage;
it's now using the stable toolchain.

.github/workflows/coverage.yml

@@ -5,55 +5,47 @@ on: [push, pull_request]
 env:
   RUST_BACKTRACE: 1
 
-jobs:  
+jobs:
   generate_coverage:
     runs-on: ubuntu-latest
 
     steps:
     - name: Checkout sources
       uses: actions/checkout@v2
-
-    - name: Install nightly toolchain pinned at 2022-01-14
-      uses: actions-rs/toolchain@v1
-      with:
-          profile: minimal
-          toolchain: nightly-2022-01-14
-          override: true
-          components: llvm-tools-preview
-
-    - name: Install cargo-llvm-cov
-      run: rustup run nightly-2022-01-14 cargo install cargo-llvm-cov
-
-    - name: Build cfitsio
+
+    - name: Install dependencies
       run: |
-          # Install dependencies
-          curl "https://heasarc.gsfc.nasa.gov/FTP/software/fitsio/c/cfitsio-3.49.tar.gz" -o cfitsio.tar.gz
-          tar -xf cfitsio.tar.gz
-          rm cfitsio.tar.gz
-          cd cfitsio-3.49
-          # Enabling SSE2/SSSE3 could cause portability problems, but it's unlikely that anyone
-          # is using such a CPU...
-          # https://stackoverflow.com/questions/52858556/most-recent-processor-without-support-of-ssse3-instructions
-          # Disabling curl just means you cannot fits_open() using a URL.
-          CFLAGS="-O3" ./configure --prefix=/usr/local --enable-reentrant --enable-sse2 --enable-ssse3 --disable-curl
-          make -j
-          sudo make install
-          sudo ldconfig
-          cd ..
-
-    - name: Install OS packages
-      run: |         
-        sudo apt-get update 
-        sudo apt-get install -y lcov clang curl zip unzip libssl-dev jq         
+        sudo apt update -y
+        sudo apt install -y \
+          tzdata \
+          build-essential \
+          pkg-config \
+          git \
+          lcov \
+          libcfitsio-dev \
+          ;
       env:
         DEBIAN_FRONTEND: noninteractive
-
-    - name: Generate test lcov coverage into coverage/ dir      
+
+    - name: Install stable toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: stable
+        override: true
+        components: llvm-tools-preview
+
+    - name: install cargo-llvm-cov
+      run: cargo install cargo-llvm-cov
+
+    - name: Generate test lcov coverage into coverage/ dir
       run: |
         mkdir -p coverage
-        rustup run nightly-2022-01-14 cargo llvm-cov --lib --ignore-filename-regex="test.rs" --lcov --output-path coverage/coverage.lcov
+        cargo llvm-cov --lib --lcov --output-path coverage/coverage.lcov
+        # this uses the result of the previous run to generate a text summary
+        cargo llvm-cov --no-run
 
     - name: Upload reports to codecov.io
-      uses: codecov/codecov-action@v1
+      uses: codecov/codecov-action@v2
       with:
         token: ${{ secrets.CODECOV_TOKEN }}

Cargo.toml

@@ -1,13 +1,13 @@
 [package]
 name = "mwalib"
-version = "0.15.0"
+version = "0.15.1"
 homepage = "https://github.com/MWATelescope/mwalib"
 repository = "https://github.com/MWATelescope/mwalib"
 readme = "README.md"
 authors = ["Greg Sleap <greg.sleap@curtin.edu.au>",
            "Christopher H. Jordan <christopherjordan87@gmail.com>"]
 edition = "2021"
-rust-version = "1.56"
+rust-version = "1.57"
 description = "A library to simplify reading Murchison Widefield Array (MWA) raw visibilities, voltages and metadata."
 license = "MPL-2.0"
 keywords = ["radioastronomy", "mwa", "astronomy"]