Avoid fips feature for docs.rs

The docs.rs environment has golang installed, but doesn't have
the environment variables needed to make it actually work:
rust-lang/docs.rs#1303

So avoid that entirely.

.github/workflows/docs.yml

@@ -34,7 +34,8 @@ jobs:
             "</script>"
 
       - name: cargo doc
-        run: cargo doc --locked --all-features --no-deps --package rustls
+        # keep features in sync with Cargo.toml `[package.metadata.docs.rs]` section
+        run: cargo doc --locked --features read_buf,ring --no-deps --package rustls
         env:
           RUSTDOCFLAGS: -Dwarnings --cfg=docsrs --html-after-content tag.html
 

rustls/Cargo.toml

@@ -61,7 +61,8 @@ harness = false
 required-features = ["ring"]
 
 [package.metadata.docs.rs]
-all-features = true
+# all non-default features except fips (cannot build on docs.rs environment)
+features = ["read_buf", "ring"]
 rustdoc-args = ["--cfg", "docsrs"]
 
 [package.metadata.cargo_check_external_types]