set version to v2.6.7

ranocha · ranocha · commit 2547e713c4b4 · 2021-12-03T15:03:20.000+01:00
diff --git a/Project.toml b/Project.toml
@@ -1,7 +1,7 @@
 name = "RootedTrees"
 uuid = "47965b36-3f3e-11e9-0dcf-4570dfd42a8c"
 authors = ["Hendrik Ranocha <mail@ranocha.de> and contributors"]
-version = "2.6.7-pre"
+version = "2.6.7"
 
 [deps]
 Latexify = "23fbe1c1-3f47-55db-b15f-69d7ec21a316"
