Add PR build check action

.github/workflows/gradle-wrapper-validation.yml

@@ -1,10 +1,11 @@
-name: "Validate Gradle Wrapper"
+name: Validate Gradle Wrapper
 on: [push, pull_request]
 
 jobs:
   validation:
-    name: "Validation"
+    name: Validation
     runs-on: ubuntu-latest
+
     steps:
       - uses: actions/checkout@v2
       - uses: gradle/wrapper-validation-action@v1

.github/workflows/issue_closer.yml

@@ -1,5 +1,6 @@
 name: Issue closer
 on: [issues]
+
 jobs:
   autoclose:
     runs-on: ubuntu-latest
@@ -31,4 +32,4 @@ jobs:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         type: body
         regex: ".*\\* (Tachiyomi version|Android version|Device): \\?.*"
-        message: "@${issue.user.login} this issue was automatically closed because the requested information was not filled out."
+        message: "@${issue.user.login} this issue was automatically closed because the requested information was not filled out."

.github/workflows/pr_build_check.yml

@@ -0,0 +1,18 @@
+name: Pull request build check
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Clone repo
+        uses: actions/checkout@v2
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Install NDK
+        run: sudo ${ANDROID_HOME}/tools/bin/sdkmanager --install "ndk;21.3.6528147"
+      - name: Build project
+        run: ./gradlew assembleDebug