Bump io.opentelemetry:opentelemetry-bom from 1.25.0 to 1.26.0 in /examples/extension (#8428)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

examples/extension/build.gradle

@@ -23,7 +23,7 @@ version '1.0'
 ext {
   versions = [
     // this line is managed by .github/scripts/update-sdk-version.sh
-    opentelemetrySdk           : "1.25.0",
+    opentelemetrySdk           : "1.26.0",
 
     // these lines are managed by .github/scripts/update-version.sh
     opentelemetryJavaagent     : "1.26.0-SNAPSHOT",