Revert "deps: Upgrade protobuf to 3.21.7 (#1048)"

This reverts commit c768691.

Author: emmileaf

PROPERTIES.bzl

@@ -1,5 +1,5 @@
 PROPERTIES = {
-    "version.com_google_protobuf": "3.21.7",
+    "version.com_google_protobuf": "3.19.1",
     # Version of google-java-format is downgraded from 1.8 to 1.7, because 1.8 supports java 11 minimum, while our JRE is java 8.
     "version.google_java_format": "1.7",
     "version.io_grpc_java": "1.42.1",
@@ -10,7 +10,7 @@ PROPERTIES = {
     "maven.com_google_auto_value_auto_value": "com.google.auto.value:auto-value:1.7.2",
     "maven.com_google_auto_value_auto_value_annotations": "com.google.auto.value:auto-value-annotations:1.7.2",
     "maven.com_google_code_gson": "com.google.code.gson:gson:2.8.6",
-    "maven.com_google_protobuf_protobuf_java": "com.google.protobuf:protobuf-java:3.21.7",
+    "maven.com_google_protobuf_protobuf_java": "com.google.protobuf:protobuf-java:3.19.1",
     "maven.io_github_java_diff_utils": "io.github.java-diff-utils:java-diff-utils:4.11",
     "maven.javax_annotation_javax_annotation_api": "javax.annotation:javax.annotation-api:1.3.2",
 

pom.xml

@@ -155,7 +155,7 @@
         <artifactId>protobuf-maven-plugin</artifactId>
         <version>0.6.1</version>
         <configuration>
-          <protocArtifact>com.google.protobuf:protoc:3.21.7:exe:${os.detected.classifier}</protocArtifact>
+          <protocArtifact>com.google.protobuf:protoc:3.19.4:exe:${os.detected.classifier}</protocArtifact>
         </configuration>
         <executions>
           <execution>