upgrade sbt to 1.4.3

SethTisue · SethTisue · commit 84fa0de96a8c · 2020-11-18T16:28:04.000-08:00
previously this was blocked by Dottydoc failing
diff --git a/project/build.properties b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.3.13
+sbt.version=1.4.3
