tox.ini: Add gentoo-python3.11

[sheerluck]

Similar to #32838 but this time thanks to docker.yml we need two one-liners only

Branch for this ticket can be formed from ​single commit in fork.

To test this ticket one needs #33842 and also to bump LT_VERSION to 3.12.0

--- a/build/pkgs/python3/spkg-configure.m4
+++ b/build/pkgs/python3/spkg-configure.m4
@@ -1,8 +1,8 @@
 SAGE_SPKG_CONFIGURE([python3], [
    m4_pushdef([MIN_VERSION],               [3.8.0])
    m4_pushdef([MIN_NONDEPRECATED_VERSION], [3.8.0])
-   m4_pushdef([LT_STABLE_VERSION],         [3.11.0])
-   m4_pushdef([LT_VERSION],                [3.11.0])
+   m4_pushdef([LT_STABLE_VERSION],         [3.12.0])
+   m4_pushdef([LT_VERSION],                [3.12.0])
    AC_ARG_WITH([python],
                [AS_HELP_STRING([--with-python=PYTHON3],
                                [Python 3 executable to use for the Sage venv; default: python3])])

and it seems like sagemath is not ready for that yet :(

Depends on #33842

Component: porting

Issue created by migration from https://trac.sagemath.org/ticket/34715

[sheerluck]

comment:1

✅ https://github.com/sheerluck/sage/actions/runs/3377922796/jobs/5607461032

[mkoeppe]

comment:2

I've cherry-picked this commit onto #33842

[mkoeppe]

Changed author from Andrey Belgorodski to none

[mkoeppe]

Dependencies: #33842