Add github workflows for audit, test and fmt

.github/workflows/audit.yml

@@ -0,0 +1,19 @@
+name: Audit
+
+on:
+  push:
+    paths:
+      - '**/Cargo.toml'
+      - '**/Cargo.lock'
+  schedule:
+    - cron: '0 0 * * 0' # Once per week
+
+jobs:
+
+  security_audit:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/audit-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/cont_integration.yml

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+on: [push, pull_request]
+
+name: CI
+
+jobs:
+
+  build-test:
+    name: Build and test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - version: 1.60.0 # STABLE
+            clippy: true
+          - version: 1.56.1 # MSRV
+    steps:
+      - name: checkout
+        uses: actions/checkout@v2
+      - name: Generate cache key
+        run: echo "${{ matrix.rust.version }} ${{ matrix.features }}" | tee .cache_key
+      - name: cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('.cache_key') }}-${{ hashFiles('**/Cargo.toml','**/Cargo.lock') }}
+      - name: Set default toolchain
+        run: rustup default ${{ matrix.rust.version }}
+      - name: Set profile
+        run: rustup set profile minimal
+      - name: Add clippy
+        if: ${{ matrix.rust.clippy }}
+        run: rustup component add clippy
+      - name: Update toolchain
+        run: rustup update
+      - name: Build
+        run: cargo build
+      - name: Clippy
+        if: ${{ matrix.rust.clippy }}
+        run: cargo clippy --all-targets -- -D warnings
+      - name: Test
+        run: cargo test
+
+  fmt:
+    name: Rust fmt
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set default toolchain
+        run: rustup default nightly
+      - name: Set profile
+        run: rustup set profile minimal
+      - name: Add rustfmt
+        run: rustup component add rustfmt
+      - name: Update toolchain
+        run: rustup update
+      - name: Check fmt
+        run: cargo fmt --all -- --config format_code_in_doc_comments=true --check