Update virtualenv requirement from >=21.3.0 to >=21.3.1

[dependabot]

Updates the requirements on virtualenv to permit the latest version.

Release notes

Sourced from virtualenv's releases.

21.3.1

What's Changed

• 👷 ci: retry transient apt failures on Linux by @​gaborbernat in pypa/virtualenv#3139
• 🐛 fix(seed): bump embedded pip to 26.1.1 by @​gaborbernat in pypa/virtualenv#3138

Full Changelog: pypa/virtualenv@21.3.0...21.3.1

Changelog

Sourced from virtualenv's changelog.

Bugfixes - 21.3.1

• Upgrade embedded wheels:

  • pip to 26.1.1 from 26.1 (:issue:3138)

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v21.3.0 (2026-04-27)

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Features - 21.3.0

• Re-introduce xonsh shell activator (activate.xsh) previously removed in 20.7.0, and make the plugin loader prefer virtualenv's built-in entry points so a third-party package cannot override them by registering a duplicate name. (:issue:3003)

Bugfixes - 21.3.0

• Upgrade embedded wheels:

  • pip to 26.1 (:issue:3132)

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v21.2.4 (2026-04-14)

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Bugfixes - 21.2.4

• Security hardening: validate each entry of a seed wheel archive before extracting it so a tampered wheel cannot escape the app-data image directory via an absolute path or .. traversal. (:issue:3118)
• Security hardening: verify the SHA-256 of every bundled seed wheel when it is loaded so a corrupted or tampered file on disk fails loud instead of being handed to pip. The hash table is generated alongside BUNDLE_SUPPORT by tasks/upgrade_wheels.py. (:issue:3119)
• Security hardening: validate the distribution name and version specifier passed to pip download when acquiring a seed wheel so extras, pip flags, or shell metacharacters cannot be smuggled into the subprocess command line. (:issue:3120)
• Security hardening: replace the string-prefix containment check in virtualenv.util.zipapp with Path.relative_to so the zipapp extraction helpers refuse any path that does not resolve under the archive root. (:issue:3121)
• Security hardening: do not silently fall back to an unverified HTTPS context when the periodic update request to PyPI fails TLS verification. The returned metadata drives which wheel version virtualenv considers "up to date", so accepting an unverified response lets a network-level attacker suppress security updates. Set VIRTUALENV_PERIODIC_UPDATE_INSECURE=1 to restore the previous behavior on hosts with broken trust stores. (:issue:3122)

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... (truncated)

Commits

• 12ab495 release 21.3.1
• 22eadc4 [pre-commit.ci] pre-commit autoupdate (#3137)
• 6651daf 🐛 fix(seed): bump embedded pip to 26.1.1 (#3138)
• 936a36a 👷 ci: retry transient apt failures on Linux (#3139)
• cb5a7d1 [pre-commit.ci] pre-commit autoupdate (#3133)
• See full diff in compare view

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