chore: update gen check workflow (#14361)

Author: JoeWang1127

.github/workflows/generation_check.yaml

@@ -17,14 +17,18 @@ jobs:
       - uses: actions/setup-go@v6
         with:
           go-version: '1.26.x'
+      - name: Install Protoc
+        uses: arduino/setup-protoc@v3
+        with:
+          version: "25.7"
       - name: Install tools
         run: |
-          go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.36.11 && \
-          go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.3.0 && \
-          go install github.com/googleapis/gapic-generator-go/cmd/protoc-gen-go_gapic@v0.57.0 && \
-          go install golang.org/x/tools/cmd/goimports@latest
-      - name: Regeneration
-        run: ./.github/workflows/regenerate.sh
+          version=$(sed -n 's/^version: *//p' librarian.yaml)
+          go run "github.com/googleapis/librarian/cmd/librarian@${version}" install
+      - name: Regenerate
+        run: |
+          version=$(sed -n 's/^version: *//p' librarian.yaml)
+          go run "github.com/googleapis/librarian/cmd/librarian@${version}" generate -all
       - name: Create issue on diff
         if: failure()
         env: