Add GitHub action to build and publish the nightly build.

Author: bmarty

.github/workflows/nightly.yml

@@ -0,0 +1,39 @@
+name: Build and release nightly APK
+
+on:
+  schedule:
+    # Every nights at 4
+    - cron: "0 4 * * *"
+
+env:
+  CI_GRADLE_ARG_PROPERTIES: >
+    -Porg.gradle.jvmargs=-Xmx4g
+    -Porg.gradle.parallel=false
+    --no-daemon
+
+jobs:
+  nightly:
+    name: Build and publish nightly Gplay APK to Firebase
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - name: Build and upload Gplay Nightly APK
+        run: |
+          mv towncrier.toml towncrier.toml.bak
+          sed 's/CHANGES\.md/CHANGES_NIGHTLY\.md/' towncrier.toml.bak > towncrier.toml
+          rm towncrier.toml.bak
+          yes n | towncrier --version nightly
+          ./gradlew assembleGplayNightly appDistributionUploadGplayNightly $CI_GRADLE_ARG_PROPERTIES --stacktrace
+        env:
+          ELEMENT_ANDROID_NIGHTLY_KEYID: ${{ secrets.ELEMENT_ANDROID_NIGHTLY_KEYID }}
+          ELEMENT_ANDROID_NIGHTLY_KEYPASSWORD: ${{ secrets.ELEMENT_ANDROID_NIGHTLY_KEYPASSWORD }}
+          ELEMENT_ANDROID_NIGHTLY_STOREPASSWORD: ${{ secrets.ELEMENT_ANDROID_NIGHTLY_STOREPASSWORD }}
+          FIREBASE_TOKEN: ${{ secrets.ELEMENT_ANDROID_NIGHTLY_FIREBASE_TOKEN }}