Update scala-library to 2.12.21 (#341)

Author: scala-steward

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         java: [ '11', '17', '21', '22' ]
-        scala: [ '2.13.18', '2.12.20', '2.11.12', '3.7.3' ]
+        scala: [ '2.13.18', '2.12.21', '2.11.12', '3.7.3' ]
     steps:
     - uses: actions/checkout@v5
     - name: Set up JDK

build.sbt

@@ -3,7 +3,7 @@ name := "jms-testkit"
 
 organization := "io.github.sullis"
 
-scalaVersion := "2.12.20"
+scalaVersion := "2.12.21"
 
 crossScalaVersions := Seq(scalaVersion.value, "2.11.12", "2.13.18", "3.7.3")