chore: Update to version 1.50.3

Author: lqiu96

java-iam/grpc-google-iam-v3/pom.xml

@@ -4,13 +4,13 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.api.grpc.api.grpc</groupId>
   <artifactId>grpc-google-iam-v3</artifactId>
-  <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
+  <version>1.50.3</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
   <name>grpc-google-iam-v3</name>
   <description>GRPC library for proto-google-iam-v1</description>
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-iam-parent</artifactId>
-    <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:proto-google-iam-v1:current} -->
+    <version>1.50.3</version><!-- {x-version-update:proto-google-iam-v1:current} -->
   </parent>
   <dependencies>
     <dependency>

java-iam/pom.xml

@@ -125,12 +125,12 @@
       <dependency>
         <groupId>com.google.api.grpc.api.grpc</groupId>
         <artifactId>proto-google-iam-v3</artifactId>
-        <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:proto-google-iam-v3:current} -->
+        <version>1.50.3</version><!-- {x-version-update:proto-google-iam-v3:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.api.grpc.api.grpc</groupId>
         <artifactId>grpc-google-iam-v3</artifactId>
-        <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
+        <version>1.50.3</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
       </dependency>
       <dependency>
         <groupId>javax.annotation</groupId>

java-iam/proto-google-iam-v3/pom.xml

@@ -4,13 +4,13 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.api.grpc.api.grpc</groupId>
   <artifactId>proto-google-iam-v3</artifactId>
-  <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:proto-google-iam-v3:current} -->
+  <version>1.50.3</version><!-- {x-version-update:proto-google-iam-v3:current} -->
   <name>proto-google-iam-v3</name>
   <description>Proto library for proto-google-iam-v1</description>
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-iam-parent</artifactId>
-    <version>1.50.3-SNAPSHOT</version><!-- {x-version-update:proto-google-iam-v1:current} -->
+    <version>1.50.3</version><!-- {x-version-update:proto-google-iam-v1:current} -->
   </parent>
   <dependencies>
     <dependency>