Add retention-days: 7 to uploaded artifacts (#1432)

by default the artifacts are kept for 90 days but for PRs we don't need to keep them for so long.
Also we can just re-run the workflow.

https://github.blog/changelog/2020-10-08-github-actions-ability-to-change-retention-days-for-artifacts-and-logs/

.github/workflows/ci.yml

@@ -71,66 +71,76 @@ jobs:
         with:
           name: ungit
           path: ungit-*.tgz
+          retention-days: 7
 
       - name: Upload ungit-darwin-x64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-darwin-x64
           path: dist/ungit-darwin-x64.zip
+          retention-days: 7
 
       - name: Upload ungit-linux-arm64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-linux-arm64
           path: dist/ungit-linux-arm64.zip
+          retention-days: 7
 
       - name: Upload ungit-linux-armv7l
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-linux-armv7l
           path: dist/ungit-linux-armv7l.zip
+          retention-days: 7
 
       - name: Upload ungit-linux-ia32
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-linux-ia32
           path: dist/ungit-linux-ia32.zip
+          retention-days: 7
 
       - name: Upload ungit-linux-x64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-linux-x64
           path: dist/ungit-linux-x64.zip
+          retention-days: 7
 
       - name: Upload ungit-mas-x64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-mas-x64
           path: dist/ungit-mas-x64.zip
+          retention-days: 7
 
       - name: Upload ungit-win32-arm64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-win32-arm64
           path: dist/ungit-win32-arm64.zip
+          retention-days: 7
 
       - name: Upload ungit-win32-ia32
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-win32-ia32
           path: dist/ungit-win32-ia32.zip
+          retention-days: 7
 
       - name: Upload ungit-win32-x64
         if: matrix.os == 'ubuntu-latest' && matrix.node-version == '10'
         uses: actions/upload-artifact@v2
         with:
           name: ungit-win32-x64
           path: dist/ungit-win32-x64.zip
+          retention-days: 7