verify golangci-lint sha256 checksum

Signed-off-by: Josh Dolitsky <josh@dolit.ski>

.github/workflows/build-pr.yml

@@ -15,11 +15,14 @@ jobs:
           go-version: '1.16'
       - name: Install golangci-lint
         run: |
-          curl -sSL https://github.com/golangci/golangci-lint/releases/download/v$GOLANGCI_LINT_VERSION/golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64.tar.gz | tar xz
+          curl -sSLO https://github.com/golangci/golangci-lint/releases/download/v$GOLANGCI_LINT_VERSION/golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64.tar.gz
+          shasum -a 256 golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64.tar.gz | grep "^$GOLANGCI_LINT_SHA256  " > /dev/null
+          tar -xf golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64.tar.gz
           sudo mv golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64/golangci-lint /usr/local/bin/golangci-lint
-          rm -rf golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64
+          rm -rf golangci-lint-$GOLANGCI_LINT_VERSION-linux-amd64*
         env:
           GOLANGCI_LINT_VERSION: '1.36.0'
+          GOLANGCI_LINT_SHA256: '9b8856b3a1c9bfbcf3a06b78e94611763b79abd9751c245246787cd3bf0e78a5'
       - name: Test style
         run: make test-style
       - name: Run unit tests