Bump io.smallrye.config:smallrye-config-source-yaml in /devtools/gradle

Bumps io.smallrye.config:smallrye-config-source-yaml from 3.11.3-SNAPSHOT to 3.12.0.

---
updated-dependencies:
- dependency-name: io.smallrye.config:smallrye-config-source-yaml
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

devtools/gradle/gradle/libs.versions.toml

@@ -3,7 +3,7 @@ plugin-publish = "1.3.1"
 
 # updating Kotlin here makes QuarkusPluginTest > shouldNotFailOnProjectDependenciesWithoutMain(Path) fail
 kotlin = "2.0.21"
-smallrye-config = "3.11.3-SNAPSHOT"
+smallrye-config = "3.12.0"
 
 junit5 = "5.10.5"
 assertj = "3.27.3"