[skip ci] pre release for converters plugin

Author: jdaugherty

gradle.properties

@@ -34,7 +34,7 @@ asset-pipeline-grails.version=5.0.5
 byte-buddy.version=1.15.5
 commons-codec.version=1.17.1
 commons-text.version=1.12.0
-converters.version=6.0.0-SNAPSHOT
+converters.version=6.0.0-M1
 directory-watcher.version=0.18.0
 flying-saucer-pdf-openpdf.version=9.4.0
 geb-spock.version=7.0