Tweak workflows

Author: Cimbali

.github/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        npm i -g web-ext
+        npm i -g web-ext yarn
         echo "`npm config get prefix`/bin" >> $GITHUB_PATH
 
     - name: Update version number for beta

.github/workflows/eslint.yml

@@ -15,5 +15,4 @@ jobs:
         run: npm i eslint-plugin-no-unsanitized@latest eslint@latest
 
       - name: Run linter
-        run: |
-          make -k FORMAT=stylish
+        run: make -k FORMAT=stylish