Add Python 3.12 support and update static typing checks

  - Use mypy==1.2.0 for static typing checks
  - Add py312, mypy-pypy3 and mypy-py312 test environments
  - py312: skip	lxml installation for now

.github/workflows/test-xmlschema.yml

@@ -47,10 +47,10 @@ jobs:
       - name: Lint with mypy if Python version != 3.7
         if: ${{ matrix.python-version != '3.7' }}
         run: |
-          pip install mypy==1.0.1 elementpath==4.0.1 lxml-stubs
+          pip install mypy==1.2.0 elementpath==4.1.1 lxml-stubs
           mypy --show-error-codes --strict xmlschema
       - name: Lint with mypy if Python version == 3.7
         if: ${{ matrix.python-version == '3.7' }}
         run: |
-          pip install mypy==1.0.1 elementpath==4.0.1 lxml-stubs
+          pip install mypy==1.2.0 elementpath==4.1.1 lxml-stubs
           mypy --show-error-codes --no-warn-redundant-casts --no-warn-unused-ignores --strict xmlschema

tox.ini

@@ -1,6 +1,6 @@
 [tox]
-envlist = py{37,38,39,310,311}, pypy3, ep{40}, docs,
-    flake8, mypy-py{37,38,39,310,311}, coverage, pytest
+envlist = py{37,38,39,310,311,312,py3}, ep{40}, docs,
+    flake8, mypy-py{37,38,39,310,311,312,py3}, coverage, pytest
 skip_missing_interpreters = true
 work_dir = {tox_root}/../.tox/xmlschema
 
@@ -15,10 +15,12 @@ deps =
     coverage: coverage
 commands =
     python -m unittest
-allowlist_externals = make
 
-[testenv:pypy3]
-commands = python -m unittest
+[testenv:py312]
+deps =
+    elementpath>=4.0.0, <5.0.0
+    # lxml: skip for now
+    jinja2
 
 [testenv:ep40]
 deps =
@@ -31,6 +33,7 @@ commands =
     make -C doc latexpdf SPHINXOPTS="-W -n"
     make -C doc doctest SPHINXOPTS="-W -n"
     sphinx-build -W -n -T -b man doc build/sphinx/man
+allowlist_externals = make
 
 [flake8]
 max-line-length = 100
@@ -44,17 +47,17 @@ commands =
 
 [testenv:mypy-py37]
 deps =
-    mypy==1.0.1
-    elementpath==4.0.1
+    mypy==1.2.0
+    elementpath==4.1.1
     lxml-stubs
     jinja2
 commands =
     mypy --config-file {toxinidir}/mypy.ini xmlschema
 
-[testenv:mypy-py{38,39,310,311}]
+[testenv:mypy-py{38,39,310,311,312,py3}]
 deps =
-    mypy==1.0.1
-    elementpath==4.0.1
+    mypy==1.2.0
+    elementpath==4.1.1
     lxml-stubs
     jinja2
 commands =
@@ -74,7 +77,7 @@ deps =
     elementpath>=4.0.0, <5.0.0
     lxml
     jinja2
-    mypy==1.0.1
+    mypy==1.2.0
     lxml-stubs
 commands =
     pytest tests -ra