Fix sdk version in release notes (#7880)

Author: trask

.github/workflows/release.yml

@@ -110,10 +110,12 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
+          sdk_version=$(grep -Po "val otelSdkVersion = \"\K[0-9]+.[0-9]+.[0-9]+" dependencyManagement/build.gradle.kts)
+
           # conditional blocks not indented because of the heredoc
           if [[ $VERSION == *.0 ]]; then
           cat > /tmp/release-notes.txt << EOF
-          This release targets the OpenTelemetry SDK $VERSION.
+          This release targets the OpenTelemetry SDK $sdk_version.
 
           Note that many artifacts have the \`-alpha\` suffix attached to their version number, reflecting that they are still alpha quality and will continue to have breaking changes. Please see the [VERSIONING.md](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/VERSIONING.md#opentelemetry-java-instrumentation-versioning) for more details.