Revert "NEP 29 > SPEC 0 in dependency policy"

Author: dstansby

doc/devel/min_dep_policy.rst

@@ -10,8 +10,8 @@ For the purpose of this document, 'minor version' is in the sense of SemVer
 major/macro and minor/meso releases.  For projects that use date-based
 versioning, every release is a 'minor version'.
 
-Matplotlib follows the recommendations in `SPEC 0
-<https://scientific-python.org/specs/spec-0000/>`__.
+Matplotlib follows `NEP 29
+<https://numpy.org/neps/nep-0029-deprecation_policy.html>`__.
 
 Python and NumPy
 ================