Remove NotNull on revision for YangResourceEntity

Issue-ID: CPS-1265
Signed-off-by: lukegleeson <luke.gleeson@est.tech>
Change-Id: Icfe4d9881a3aa7d92d5bd17eaaed91bdbce0a203
(cherry picked from commit 8c6b5627652a4f3b4926b8c425e4c1036ac1e570)
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/entities/YangResourceEntity.java b/cps-ri/src/main/java/org/onap/cps/spi/entities/YangResourceEntity.java
index 032745b..9dab51a 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/entities/YangResourceEntity.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/entities/YangResourceEntity.java
@@ -66,7 +66,6 @@
     @Column
     private String moduleName;
 
-    @NotNull
     @Column
     private String revision;