Add reuse compliance checking

Add reuse compliance checking to PR actions.

Author: soimkim

.github/workflows/pull-request.yml

@@ -8,12 +8,10 @@ on:
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
     strategy:
       matrix:
         python-version: [3.6]
-
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
@@ -27,3 +25,9 @@ jobs:
     - name: Run Tox
       run: |
         tox -e release
+  reuse:
+    runs-on: ubuntu-latest
+    steps: 
+    - uses: actions/checkout@v2
+    - name: REUSE Compliance Check
+      uses: fsfe/reuse-action@v1