Add "deprecation" to possible changelog entries in pre-commit

Author: nicoddemus

.pre-commit-config.yaml

@@ -41,5 +41,5 @@ repos:
         name: changelog filenames
         language: fail
         entry: 'changelog files must be named ####.(feature|bugfix|doc|removal|vendor|trivial).rst'
-        exclude: changelog/(\d+\.(feature|bugfix|doc|removal|vendor|trivial).rst|README.rst|_template.rst)
+        exclude: changelog/(\d+\.(feature|bugfix|doc|deprecation|removal|vendor|trivial).rst|README.rst|_template.rst)
         files: ^changelog/