test: adding java 7 build

.github/workflows/ci-java7.yaml

@@ -0,0 +1,35 @@
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# Github action job to test core java library features on
+# downstream client libraries before they are released.
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+name: ci-java7
+jobs:
+  units:
+    name: "units (7)"
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/setup-java@v3
+      with:
+        distribution: adoptopenjdk
+        java-version: '7'
+    - run: java -version
+    - run: .kokoro/build.sh
+      env:
+        JOB_TYPE: test