Fix publish versions plugin and add CONTRIBUTING.md. (#1)

Align with core-java: use org.codehaus.mojo versions-maven-plugin and document contribution policy.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: cfluke-cb

.github/workflows/publish.yml

@@ -51,7 +51,7 @@ jobs:
             echo "Release tag must be vX.Y.Z (for example v1.2.0)" >&2
             exit 1
           fi
-          mvn -B org.apache.maven.plugins:maven-versions-plugin:2.17.1:set \
+          mvn -B org.codehaus.mojo:versions-maven-plugin:2.17.1:set \
             -DnewVersion="$VERSION" \
             -DgenerateBackupPoms=false
         env:

CONTRIBUTING.md

@@ -0,0 +1,5 @@
+# Contributing to prime-sdk-java
+
+At this time we are not accepting Pull Requests. Therefore, if you have an idea for a new feature or have found a non-security bug, please open an issue. We will examine the issue and determine if it is a good fit for the project and if it is, we will provide the change internally and release it to the public.
+
+If you have found a security bug, please refer to the [security policy](SECURITY.md) for how to report it.