Bumps bleach from 2.1.3 to 3.1.1.

Sourced from bleach's changelog.

Version 3.1.1 (February 13th, 2020)

Security fixes

• bleach.clean behavior parsing noscript tags did not match
  browser behavior.

  Calls to bleach.clean allowing noscript and one or more of
  the raw text tags (title, textarea, script, style,
  noembed, noframes, iframe, and xmp) were vulnerable
  to a mutation XSS.

  This security issue was confirmed in Bleach versions v2.1.4, v3.0.2,
  and v3.1.0. Earlier versions are probably affected too.

  Anyone using Bleach <=v3.1.0 is highly encouraged to upgrade.

  https://bugzilla.mozilla.org/show_bug.cgi?id=1615315

Backwards incompatible changes

None

Features

None

Bug fixes

None

Bleach changes

Version 3.1.0 (January 9th, 2019)

Security fixes

None

Backwards incompatible changes

None

Features

• Add recognized_tags argument to the linkify Linker class. This
  fixes issues when linkifying on its own and having some tags get escaped.

... (truncated)

• 0d88dd8 Update for v3.1.1 release
• 996cde7 fix bug 1615315
• 2f210e0 Merge pull request #435 from willkg/3_1_0_release
• ad910ce Update for 3.1.0 release
• 948b745 Merge pull request #433 from willkg/357-doctest
• 245c21c Fix doctest failures
• cabd665 Merge pull request #432 from willkg/431-charencoding
• cb156cb Fix parsing "meta" tag with encoding attribute
• 93a060e Merge pull request #429 from willkg/422-amp
• 8d7fd48 Convert & to & as a Characters token
• Additional commits viewable in compare view

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