Update scala3-library, ... to 3.4.3 (#611)

Co-authored-by: eikek-scala-steward <[email protected]>

Author: eikek-scala-steward[bot]

build.sbt

@@ -2,7 +2,7 @@ import com.github.sbt.git.SbtGit.GitKeys
 
 val scala212 = "2.12.20"
 val scala213 = "2.13.14"
-val scala3 = "3.4.2"
+val scala3 = "3.4.3"
 
 val updateReadme = inputKey[Unit]("Update readme")