chore: set up release-please (#4)

Based on rust-bio/rust-bio#436 and
https://github.com/google-github-actions/release-please-action

Bit of a trial for sourmash-bio/sourmash#2425

.github/workflows/conventional-prs.yml

@@ -0,0 +1,16 @@
+name: PR
+on:
+  pull_request_target:
+    types:
+      - opened
+      - reopened
+      - edited
+      - synchronize
+
+jobs:
+  title-format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: amannn/action-semantic-pull-request@v3.4.0
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/release-please.yml

@@ -0,0 +1,40 @@
+on:
+  push:
+    branches:
+      - latest
+
+permissions:
+  contents: write
+  pull-requests: write
+
+name: release-please
+
+jobs:
+  release-please:
+    if: github.repository_owner == 'sourmash-bio'
+    runs-on: ubuntu-latest
+    steps:
+
+      - uses: GoogleCloudPlatform/release-please-action@v2
+        id: release
+        with:
+          release-type: rust
+          package-name: mastiff-client
+
+      - uses: actions/checkout@v2
+        if: ${{ steps.release.outputs.release_created }}
+
+      - name: Install stable toolchain
+        uses: actions-rs/toolchain@v1
+        if: ${{ steps.release.outputs.release_created }}
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Install system dependencies
+        if: ${{ steps.release.outputs.release_created }}
+        run: |
+            sudo apt-get install --yes zlib1g-dev libbz2-dev musl musl-dev musl-tools clang libc6-dev
+
+      - uses: Swatinem/rust-cache@v1.3.0
+        if: ${{ steps.release.outputs.release_created }}