Add missing dev0 tag to version.

NEWS

@@ -1,4 +1,4 @@
-1.9.11
+1.9.11.dev0
  * Add credential loading from file, KeePassXC, and Docker/Podman secrets. See the documentation for
    more information: https://torsion.org/borgmatic/docs/how-to/provide-your-passwords/
 1.9.10

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "borgmatic"
-version = "1.9.11"
+version = "1.9.11.dev0"
 authors = [
   { name="Dan Helfman", email="witten@torsion.org" },
 ]