chore(bazel): update protobuf to v3.21.3 (#442)

- [ ] Regenerate this pull request now.

chore(bazel): update gax-java to 2.18.4

PiperOrigin-RevId: 463115700

Source-Link: googleapis/googleapis@52130a9

Source-Link: googleapis/googleapis-gen@6a4d9d9
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiNmE0ZDlkOWJiM2FmYjIwYjBmNWZhNGY1ZDlmNjc0MGIxZDBlYjE5YSJ9

java-security-private-ca/proto-google-cloud-security-private-ca-v1/src/main/java/com/google/cloud/security/privateca/v1/CertificateExtensionConstraints.java

@@ -1269,8 +1269,8 @@ public int getKnownExtensionsValue(int index) {
      * repeated .google.cloud.security.privateca.v1.CertificateExtensionConstraints.KnownCertificateExtension known_extensions = 1 [(.google.api.field_behavior) = OPTIONAL];
      * </code>
      *
-     * @param index The index of the value to return.
-     * @return The enum numeric value on the wire of knownExtensions at the given index.
+     * @param index The index to set the value at.
+     * @param value The enum numeric value on the wire for knownExtensions to set.
      * @return This builder for chaining.
      */
     public Builder setKnownExtensionsValue(int index, int value) {