Bump scala.version from 2.12.13 to 2.13.8

Bumps `scala.version` from 2.12.13 to 2.13.8.

Updates `scala-library` from 2.12.13 to 2.13.8
- [Release notes](https://github.com/scala/scala/releases)
- [Commits](scala/scala@v2.12.13...v2.13.8)

Updates `scala-reflect` from 2.12.13 to 2.13.8
- [Release notes](https://github.com/scala/scala/releases)
- [Commits](scala/scala@v2.12.13...v2.13.8)

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

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

zoltar-bom/pom.xml

@@ -13,7 +13,7 @@
   <properties>
     <apiclient.version>1.32.1</apiclient.version>
     <boringssl.version>2.0.38.Final</boringssl.version>
-    <errorprone.version>2.7.1</errorprone.version>
+    <errorprone.version>2.11.0</errorprone.version>
     <featran.version>0.8.0-RC2</featran.version>
     <google.auth.version>0.26.0</google.auth.version>
     <grpc.version>1.39.0</grpc.version>
@@ -24,8 +24,8 @@
     <joda.version>2.10.10</joda.version>
     <netty.version>4.1.52.Final</netty.version>
     <opencensus.version>0.28.3</opencensus.version>
-    <proto.version>3.17.3</proto.version>
-    <scala.version>2.12.13</scala.version>
+    <proto.version>3.19.4</proto.version>
+    <scala.version>2.13.8</scala.version>
     <scio.version>0.5.7</scio.version>
     <tensorFlow.version>0.4.0</tensorFlow.version>
     <xgboost.version>1.3.1</xgboost.version>