updated .gitignore. set sbt version to 1.9.9 to allow building with scala 2.13.8

.gitignore

@@ -323,6 +323,38 @@ fabric.properties
 
 # End of https://www.toptal.com/developers/gitignore/api/intellij
 
+# Created by https://www.toptal.com/developers/gitignore/api/sbt
+# Edit at https://www.toptal.com/developers/gitignore?templates=sbt
+
+### SBT ###
+# Simple Build Tool
+# http://www.scala-sbt.org/release/docs/Getting-Started/Directories.html#configuring-version-control
+
+dist/*
+target/
+lib_managed/
+src_managed/
+project/boot/
+project/plugins/project/
+.history
+.cache
+.lib/
+
+### SBT Patch ###
+.bsp/
+
+# End of https://www.toptal.com/developers/gitignore/api/sbt
+
+# Created by https://www.toptal.com/developers/gitignore/api/metals
+# Edit at https://www.toptal.com/developers/gitignore?templates=metals
+
+### Metals ###
+.metals/
+.bloop/
+project/**/metals.sbt
+
+# End of https://www.toptal.com/developers/gitignore/api/metals
+
 ### Python extra ###
 local_settings*.py
 

project/build.properties

+sbt.version=1.9.9