Add release workflow for contract wasms (#17)

* Add release workflow for contract wasms

Builds contracts on version tag push and attaches wasm
artifacts to a GitHub release.

* Add cross-repo E2E trigger on release

* Add auto-tag workflow on version bump

Reads version from Cargo.toml on push to main and creates
a git tag if it doesn't already exist.

Author: AquiGorka

.github/workflows/auto-tag.yml

@@ -0,0 +1,39 @@
+name: Auto Tag
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "Cargo.toml"
+
+jobs:
+  tag:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Read version from Cargo.toml
+        id: version
+        run: |
+          VERSION=$(grep -m1 '^version' Cargo.toml | sed 's/.*"\(.*\)"/\1/')
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          echo "tag=v$VERSION" >> "$GITHUB_OUTPUT"
+
+      - name: Check if tag exists
+        id: check
+        run: |
+          if git rev-parse "refs/tags/${{ steps.version.outputs.tag }}" >/dev/null 2>&1; then
+            echo "exists=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "exists=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Create tag
+        if: steps.check.outputs.exists == 'false'
+        run: |
+          git tag ${{ steps.version.outputs.tag }}
+          git push origin ${{ steps.version.outputs.tag }}

.github/workflows/release.yml

@@ -0,0 +1,55 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build-and-release:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32v1-none
+
+      - name: Cache cargo
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            ~/.cargo/bin
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
+      - name: Install Stellar CLI
+        run: cargo install --locked stellar-cli --features opt
+
+      - name: Build contracts
+        run: stellar contract build
+
+      - name: Prepare artifacts
+        run: |
+          mkdir -p artifacts
+          cp target/wasm32v1-none/release/channel_auth_contract.wasm artifacts/
+          cp target/wasm32v1-none/release/privacy_channel.wasm artifacts/
+
+      - name: Create release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: artifacts/*.wasm
+          generate_release_notes: true
+
+      - name: Trigger E2E tests
+        uses: peter-evans/repository-dispatch@v3
+        with:
+          token: ${{ secrets.E2E_TRIGGER_TOKEN }}
+          repository: ${{ github.repository_owner }}/local-dev
+          event-type: module-release
+          client-payload: '{"module": "soroban-core", "version": "${{ github.ref_name }}"}'