chore: adds lesson 04 pr check (code-differently#126)

Signed-off-by: Anthony D. Mays <[email protected]>

.github/workflows/check_lesson_04_pr.yml

@@ -0,0 +1,32 @@
+name: Check Lesson 04 Pull Request
+
+on:
+ pull_request:
+ branches: [ "main" ]
+ paths:
+ - "lesson_04/expression/**"
+
+jobs:
+ build:
+
+ runs-on: ubuntu-latest
+ permissions:
+ contents: read
+
+ steps:
+ - uses: actions/checkout@v4
+ - name: Set up JDK 17
+ uses: actions/setup-java@v4
+ with:
+ java-version: '17'
+ distribution: 'temurin'
+
+ # Configure Gradle for optimal use in GiHub Actions, including caching of downloaded dependencies.
+ # See: https://github.com/gradle/actions/blob/main/setup-gradle/README.md
+ - name: Setup Gradle
+ uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # v3.1.0
+
+ - name: Build Lesson 04 with Gradle Wrapper
+ working-directory: ./lesson_04/expression
+ run: ./gradlew check
+