Build: Bump Qt6 from 6.8.1 to 6.8.3

Author: actions-user

.github/autobuild/windows.ps1

@@ -49,7 +49,7 @@ $DownloadCacheDir = 'C:\AutobuildCache'
 # The following version pinnings are semi-automatically checked for
 # updates. Verify .github/workflows/bump-dependencies.yaml when changing those manually:
 $Qt32Version = "5.15.2"
-$Qt64Version = "6.8.1"
+$Qt64Version = "6.8.3"
 $AqtinstallVersion = "3.1.21"
 $JackVersion = "1.9.22"
 $Msvc32Version = "win32_msvc2019"

.github/workflows/autobuild.yml

@@ -227,7 +227,7 @@ jobs:
           - config_name:            MacOS (artifacts)
             target_os:              macos
             building_on_os:         macos-14
-            base_command:           QT_VERSION=6.8.1 SIGN_IF_POSSIBLE=1 TARGET_ARCHS="x86_64 arm64" ./.github/autobuild/mac.sh
+            base_command:           QT_VERSION=6.8.3 SIGN_IF_POSSIBLE=1 TARGET_ARCHS="x86_64 arm64" ./.github/autobuild/mac.sh
             # Disable CodeQL on mac as it interferes with signing the binaries (signing hangs, see #2563 and #2564)
             run_codeql:             false
             # Latest Xcode which runs on macos-14:
@@ -251,7 +251,7 @@ jobs:
           - config_name:            iOS (artifacts)
             target_os:              ios
             building_on_os:         macos-14
-            base_command:           QT_VERSION=6.7.3 ./.github/autobuild/ios.sh
+            base_command:           QT_VERSION=6.8.3 ./.github/autobuild/ios.sh
             # Build failed with CodeQL enabled when last tested 03/2022 (#2490).
             # There are no hints that iOS is supposed to be supported by CodeQL.
             # Therefore, disable it: