Bump version.opentelemetry.instrumentation from 2.5.0 to 2.8.0

Bumps `version.opentelemetry.instrumentation` from 2.5.0 to 2.8.0.

Updates `io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom` from 2.5.0 to 2.8.0
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](open-telemetry/opentelemetry-java-instrumentation@v2.5.0...v2.8.0)

Updates `io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha` from 2.5.0-alpha to 2.8.0-alpha
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

---
updated-dependencies:
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -16,7 +16,7 @@
 
     <properties>
         <version.opentelemetry>1.39.0</version.opentelemetry>
-        <version.opentelemetry.instrumentation>2.5.0</version.opentelemetry.instrumentation>
+        <version.opentelemetry.instrumentation>2.8.0-alpha</version.opentelemetry.instrumentation>
         <version.opentelemetry.semconv>1.25.0-alpha</version.opentelemetry.semconv>
         <version.microprofile.opentelemetry>2.0</version.microprofile.opentelemetry>
         <version.microprofile.config>3.1</version.microprofile.config>
@@ -70,7 +70,7 @@
             <dependency>
                 <groupId>io.opentelemetry.instrumentation</groupId>
                 <artifactId>opentelemetry-instrumentation-bom-alpha</artifactId>
-                <version>${version.opentelemetry.instrumentation}-alpha</version>
+                <version>${version.opentelemetry.instrumentation}</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>