Add code owners and test coverage (#15)

*Issue #, if available:*

*Description of changes:* Codecov v4 requires a token to push data to
codecov.io. I've elected to store it in GitHub secrets since the token
is not particularly sensitive.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

.github/actions-rs/grcov.yml

@@ -0,0 +1,2 @@
+output-type: lcov
+output-file: ./lcov.info

.github/workflows/rust.yml

@@ -12,14 +12,30 @@ env:
 jobs:
   build:
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          override: true
+          components: rustfmt, clippy
       - name: Build
         run: cargo build --verbose
       - name: Run tests
-        run: cargo test --verbose
+        run: cargo test --verbose --all-features --no-fail-fast
+        env:
+          CARGO_INCREMENTAL: '0'
+          RUSTFLAGS: "-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests"
+          RUSTDOCFLAGS: "-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests"
+      - name: Code Coverage
+        uses: actions-rs/grcov@v0.1
+      - name: Publish Code Coverage
+        uses: codecov/codecov-action@v4
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
       - name: Lint
         run: cargo fmt --all -- --check

CODEOWNERS

@@ -0,0 +1,3 @@
+**/README.md @ecraw-amzn
+
+* @aws/aws-secrets-manager-pr-br