ci.yml: changes

Change image to ubuntu-latest.
Remove redundant :latest from container.
Make python3 pip install into one less line.
Add -j to make to speed it up.
Replace cd with working-directory and remove unneeded cd.
Add if-no-files-found: error to upload-artifact.

.github/workflows/ci.yml

@@ -4,8 +4,8 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-18.04
-    container: devkitpro/devkitarm:latest
+    runs-on: ubuntu-latest
+    container: devkitpro/devkitarm
 
     steps:
       - uses: actions/checkout@v1
@@ -23,21 +23,20 @@ jobs:
           apt-get -y install python3 python3-pip p7zip-full libarchive13
           python3 --version
           python3 -m pip install --upgrade pip setuptools
-          python3 -m pip install cryptography
-          python3 -m pip install git+https://github.com/TuxSH/firmtool.git
+          python3 -m pip install cryptography git+https://github.com/TuxSH/firmtool.git
 
       - name: Build Project
-        run: make release
+        run: make release -j$(nproc)
 
       - name: Prepare build artifact
+        working-directory: release
         run: |
-          cd release
           ZIPNAME=$(ls GodMode9-*.zip)
           rm $ZIPNAME
           echo "OUTNAME=${ZIPNAME%.zip}" >> $GITHUB_ENV
-          cd ..
 
       - uses: actions/upload-artifact@v2
         with:
           name: ${{ env.OUTNAME }}
           path: release/*
+          if-no-files-found: error