Update scala-library to 2.12.21

Author: scala-steward

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.12.20, 2.13.18, 3.3.7]
+        scala: [2.12.21, 2.13.18, 3.3.7]
         java: [zulu@11]
     runs-on: ${{ matrix.os }}
     steps:

build.sbt

@@ -21,7 +21,7 @@ inThisBuild(
 
 def crossPlugin(x: sbt.librarymanagement.ModuleID) = compilerPlugin(x.cross(CrossVersion.full))
 
-val Scala212 = "2.12.20"
+val Scala212 = "2.12.21"
 val Scala213 = "2.13.18"
 val Scala3 = "3.3.7"