github: add workflow actions for style checks

This replicates some of the TS-internal CI checks directly on github
for faster feedback.

Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

.github/workflows/git.yaml

@@ -0,0 +1,35 @@
+# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+name: Git
+
+on: [pull_request]
+
+jobs:
+  gitlint:
+    name: Gitlint
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 2
+    - run: |
+        git fetch --depth 1 --no-tags origin +refs/heads/${{ github.base_ref }}:refs/heads/${{ github.base_ref }}
+    - uses: actions/setup-python@v1
+      with:
+        python-version: '3.7'
+    - name: Install gitlint
+      run: pip install gitlint
+    - name: Run gitlint
+      run: gitlint --commits ${{ github.base_ref }}..${{ github.event.pull_request.head.sha }} lint
+
+  whitespace:
+    name: Trailing Whitespace
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - run: |
+        git fetch --depth 1 --no-tags origin +refs/heads/${{ github.base_ref }}:refs/heads/${{ github.base_ref }}
+    - name: Check
+      run: git diff --check ${{ github.base_ref }}

.github/workflows/license.yaml

@@ -0,0 +1,20 @@
+# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+name: License
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  check:
+    name: License Check
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Check
+      uses: fsfe/reuse-action@master

.github/workflows/style.yaml

@@ -0,0 +1,47 @@
+# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+name: Style
+
+on:
+  pull_request:
+
+jobs:
+  style:
+    name: Check Style
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: technote-space/get-diff-action@v1
+    - uses: actions/checkout@v2
+      with:
+        repository: seL4/sel4_tools
+        path: sel4_tools
+    - uses: actions/setup-python@v1
+      with:
+        python-version: '3.7'
+    - name: Install python packages
+      run: pip install sel4-deps
+    - name: Install astyle
+      run: sudo apt-get install astyle
+    - name: Run style check
+      run: |
+        sel4_tools/misc/style-all.sh ${{ env.GIT_DIFF }}
+        [ -z "$(git status -u no --porcelain)" ] || (git diff; exit 1)
+
+  shell:
+    name: Check shell scripts
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: technote-space/get-diff-action@v1
+    - uses: actions/checkout@v2
+      with:
+        repository: seL4/sel4_tools
+        path: sel4_tools
+    - name: Install
+      run: sudo apt-get install devscripts
+    - name: Run shell script check
+      run: |
+        sel4_tools/misc/is-valid-shell-script ${{ env.GIT_DIFF }}