Update ci.yaml, switched to using latest cross.

.github/workflows/ci.yaml

@@ -85,16 +85,12 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.rust }}
           override: true
-          components: rustfmt, clippy, rust-src
+          components: rustfmt, clippy
 
       - name: Use Cross
         if: matrix.target != '' && matrix.build != 'wasm32'
         run: |
-          # We used to install 'cross' from master, but it kept failing. So now
-          # we build from a known-good version until 'cross' becomes more stable
-          # or we find an alternative. Notably, between v0.2.1 and current
-          # master (2022-06-14), the number of Cross's dependencies has doubled.
-          cargo install --bins --git https://github.com/rust-embedded/cross --tag v0.2.1
+          cargo install cross
           echo "CARGO=cross" >> $GITHUB_ENV
           echo "TARGET_FLAGS=--target ${{ matrix.target }}" >> $GITHUB_ENV
           echo "TARGET_DIR=./target/${{ matrix.target }}" >> $GITHUB_ENV