Re-add support for deploying with CI

Signed-off-by: Graham <gpe@openrs2.org>

.github/workflows/build.yaml

@@ -4,6 +4,10 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/cache@v3
+        with:
+          path: ~/.ssh/known_hosts
+          key: ssh-known-hosts
       - uses: actions/checkout@v3
       - uses: actions/setup-java@v3
         with:
@@ -13,3 +17,18 @@ jobs:
       - uses: gradle/gradle-build-action@v2
         with:
           arguments: build
+      - if: github.ref == 'refs/heads/master'
+        run: |
+          install -dm0700 ~/.ssh
+          touch ~/.ssh/id_ed25519
+          chmod 0600 ~/.ssh/id_ed25519
+          echo "${SSH_KEY}" > ~/.ssh/id_ed25519
+        env:
+          SSH_KEY: ${{ secrets.SSH_KEY }}
+      - if: github.ref == 'refs/heads/master'
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: publish
+        env:
+          ORG_GRADLE_PROJECT_openrs2Username: ${{ secrets.REPO_USERNAME }}
+          ORG_GRADLE_PROJECT_openrs2Password: ${{ secrets.REPO_PASSWORD }}