chore(deps): bump org.scala-lang:scala-library from 2.12.20 to 2.12.21

Bumps [org.scala-lang:scala-library](https://github.com/scala/scala) from 2.12.20 to 2.12.21.
- [Release notes](https://github.com/scala/scala/releases)
- [Commits](scala/scala@v2.12.20...v2.12.21)

---
updated-dependencies:
- dependency-name: org.scala-lang:scala-library
  dependency-version: 2.12.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

client-scala/cross/2.12/pom.xml

@@ -72,7 +72,7 @@
   </scm>
 
   <properties>
-    <scala.version>2.12.20</scala.version>
+    <scala.version>2.12.21</scala.version>
   </properties>
 
   <build>

client-scala/cross/2.13/pom.xml

@@ -72,7 +72,7 @@
   </scm>
 
   <properties>
-    <scala.version>2.13.11</scala.version>
+    <scala.version>2.12.21</scala.version>
   </properties>
 
   <build>