ci: bump virtualenv from 20.26.4 to 20.26.5 in /.github/workflows (#156)

Author: dependabot[bot]

.github/workflows/constraints.txt

@@ -2,6 +2,6 @@ pip==24.2
 nox==2024.4.15
 nox-poetry==1.0.3
 poetry==1.8.3
-virtualenv==20.26.4
+virtualenv==20.26.5
 poetry-dynamic-versioning==1.4.1
 toml==0.10.2