GEODE-10089: Bump version to 1.15.1

As part of the Geode Release Process, the geode-examples build number
must be rolled forward as work begins on the next release
diff --git a/gradle.properties b/gradle.properties
index 789d5a1..6d22f45 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -14,8 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-version = 1.15.0-build.0
-geodeVersion = 1.15.0
+version = 1.15.1-build.0
+geodeVersion = 1.15.+
 
 # release properties, set these on the command line to validate against
 # a release candidate