Use MC to upload staging files

.github/workflows/build_prepare.yaml

@@ -65,12 +65,18 @@ jobs:
                     find scripts/hak -type f -print0 | sort -z | xargs -0 sha1sum >> hakHash
                   fi
 
-            - uses: ChristopherHX/gitea-upload-artifact@v4
-              with:
-                  name: webapp
-                  retention-days: 1
-                  path: |
-                      webapp.asar
-                      package.json
-                      electronVersion
-                      hakHash
+            - name: Install and configure MinIO Client
+              env:
+                S3_AK: ${{ secrets.S3_AK }}
+                S3_SK: ${{ secrets.S3_SK }}
+              run: |
+                wget https://dl.min.io/client/mc/release/linux-amd64/mc
+                chmod +x mc
+                ./mc alias set s3 https://s3.piskot.si $S3_AK $S3_SK
+
+            - name: Upload files to S3
+              run: |
+                ./mc cp webapp.asar s3/element-desktop/staging/
+                ./mc cp package.json s3/element-desktop/staging/
+                ./mc cp electronVersion s3/element-desktop/staging/
+                ./mc cp hakHash s3/element-desktop/staging/