Bump nox from 2025.2.9 to 2025.5.1 in /.github/workflows (#571)

Author: dependabot[bot]

.github/workflows/constraints.txt

@@ -1,4 +1,4 @@
 lockfile<0.13.0,>=0.12.2
 pip==25.0.1
-nox==2025.2.9
+nox==2025.5.1
 virtualenv==20.31.2