Rename master to main, use 3.10 final, add workflow_dispatch

tox.ini

@@ -1,5 +1,6 @@
 [tox]
 envlist =
+    lint
     py{py3, 310, 39, 38, 37, 36}
 
 [testenv]
@@ -13,12 +14,6 @@ extras =
 commands =
     pytest -v -s -W all --cov pylast --cov tests --cov-report term-missing --random-order {posargs}
 
-[testenv:venv]
-deps =
-    ipdb
-commands =
-    {posargs}
-
 [testenv:lint]
 passenv =
     PRE_COMMIT_COLOR
@@ -27,3 +22,9 @@ deps =
     pre-commit
 commands =
     pre-commit run --all-files --show-diff-on-failure
+
+[testenv:venv]
+deps =
+    ipdb
+commands =
+    {posargs}