tox: remove isolated_build setting

bluetech · bluetech · commit 2986ca4454ec · 2025-10-23T17:28:04.000+03:00
According to https://tox.wiki/en/stable/upgrading.html#removed-tox-ini-keys: "Isolated builds are now always used."
diff --git a/tox.ini b/tox.ini
@@ -1,5 +1,4 @@
 [tox]
-isolated_build = True
 requires = tox>=4
 envlist =
     linting
