Reduce size of cargo deps cache, by excluding ~/.cargo/registry/src.

.github/workflows/build_and_test.yml

@@ -94,12 +94,17 @@ jobs:
           tar -xf ./postgres-artifact/pg.tgz -C ./tmp_install/
           rm -rf ./postgres-artifact/
 
+      # Don't include the ~/.cargo/registry/src directory. It contains just
+      # uncompressed versions of the crates in ~/.cargo/registry/cache
+      # directory, and it's faster to let 'cargo' to rebuild it from the
+      # compressed crates.
       - name: Cache cargo deps
         id: cache_cargo
         uses: actions/cache@v3
         with:
           path: |
             ~/.cargo/registry/
+            !~/.cargo/registry/src
             ~/.cargo/git/
             target/
           # Fall back to older versions of the key, if no cache for current Cargo.lock was found
@@ -299,6 +304,7 @@ jobs:
         with:
           path: |
             ~/.cargo/registry/
+            !~/.cargo/registry/src
             ~/.cargo/git/
             target/
           key: v2-${{ runner.os }}-${{ matrix.build_type }}-cargo-${{ matrix.rust_toolchain }}-${{ hashFiles('Cargo.lock') }}

.github/workflows/codestyle.yml

@@ -98,6 +98,7 @@ jobs:
         with:
           path: |
             ~/.cargo/registry
+            !~/.cargo/registry/src
             ~/.cargo/git
             target
           key: ${{ runner.os }}-cargo-${{ hashFiles('./Cargo.lock') }}-rust-${{ matrix.rust_toolchain }}