[misc] update version to 4.0

* With the removal of Windows 7 support, wrong platform archs in the check for updates
  (that has now been fixed) and switch to an x86_64 default MinGW binary, we have enough
  breaking changes to warrant a version bump for the major. So just do that.
* Also fix a couple Coverity warnings and update a URL.

.github/workflows/mingw.yml

@@ -32,8 +32,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - { sys: mingw64, env: x86_64 }
-          - { sys: mingw32, env: i686 }
+          - { sys: mingw64, env: x86_64, exe: rufus.exe }
+          - { sys: mingw32, env: i686, exe: rufus_x86.exe }
 
     defaults:
       run:
@@ -76,22 +76,22 @@ jobs:
       run: |
         ./configure --disable-debug ${{ steps.set_alpha.outputs.option }} ${{ steps.set_beta.outputs.option }}
         make -j4
-        mv ./src/rufus.exe .
-        strip ./rufus.exe
-        upx --lzma --best ./rufus.exe
+        mv ./src/rufus.exe ./${{ matrix.exe }}
+        strip ./${{ matrix.exe }}
+        upx --lzma --best ./${{ matrix.exe }}
 
     - name: Display SHA-256
-      run: sha256sum ./rufus.exe
+      run: sha256sum ./${{ matrix.exe }}
 
     - name: Upload to VirusTotal
+      if: ${{ github.event_name == 'push' }}
       continue-on-error: true
-      if: ${{ matrix.env == 'i686' && github.event_name == 'push' }}
       run: |
-        curl --request POST --url https://www.virustotal.com/vtapi/v2/file/scan --form apikey=${{ secrets.VIRUSTOTAL_API_KEY }} --form file=@./rufus.exe
-        curl --request POST --url https://www.virustotal.com/api/v3/monitor/items --header 'x-apikey: ${{ secrets.VIRUSTOTAL_API_KEY }}' --form path='/rufus.exe' --form file=@./rufus.exe
+        curl --request POST --url https://www.virustotal.com/vtapi/v2/file/scan --form apikey=${{ secrets.VIRUSTOTAL_API_KEY }} --form file=@./${{ matrix.exe }}
+        curl --request POST --url https://www.virustotal.com/api/v3/monitor/items --header 'x-apikey: ${{ secrets.VIRUSTOTAL_API_KEY }}' --form path='/${{ matrix.exe }}' --form file=@./${{ matrix.exe }}
 
     - name: Upload artifacts
-      if: ${{ matrix.env == 'i686' && github.event_name == 'push' }}
+      if: ${{ github.event_name == 'push' }}
       uses: actions/upload-artifact@v3
       with:
         name: MinGW