Update tested and supported python versions

Author: birgits

.travis.yml

@@ -2,9 +2,9 @@ language: python
 
 matrix:
   include:
-    - python: 3.6
-    - python: 3.7
-    - python: 3.8
+    - python: 3.10
+    - python: 3.11
+    - python: 3.12
 
 # command to install dependencies
 #before_install:

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.black]
 line-length = 79
-target-version = ['py36', 'py37', 'py38']
+target-version = ['py310', 'py311', 'py312']
 include = '\.pyi?$'
 exclude = '''
 /(