Add changelog snippet: Drop Support for python 3.6

changes/changelog.d/python36.removal

@@ -0,0 +1,2 @@
+This release removes support for Python 3.6. Please make sure you update your python version before
+Updating Funkwhale!

pyproject.toml

@@ -42,5 +42,10 @@
         name = "Other"
         showcontent = true
 
+    [[tool.towncrier.type]]
+        directory = "removal"
+        name = "Removal"
+        showcontent = true
+
 [tool.black]
     exclude = "(.git|.hg|.mypy_cache|.tox|.venv|_build|buck-out|build|dist|migrations|data)"