Downgrade vendored html5lib to 1.1

Per e08f471 it appears it was intended to vendor html5lib==1.1, but
instead the commit after 1.1 seems to have been vendored.

Rather than vendoring a random revision from git, downgrade to the
actual release, which is merely changes the version number.

The removal of html5lib/LICENSE.md here is purely because vendoring is
now looking purely at the wheel for the license, rather than the
entire repository, thus it no longer picks up the license in
benchmarks/data/wpt/LICENSE.md, as no part of that directory is in the
distribution package.

tools/requirements_vendor.txt

@@ -4,10 +4,7 @@ certifi==2018.4.16
 exceptiongroup==1.2.1
 h2==4.1.0
 hpack==4.0.0
-
-# This is commit _after_ the 1.1 release, probably due to a mistake during vendoring html5lib previously.
-html5lib @ git+https://github.com/html5lib/html5lib-python.git@f4646e6ed4eeb9780f67d2083d0c09c8fffbec53
-
+html5lib==1.1
 hyperframe==6.0.1
 importlib-metadata==2.1.0
 iniconfig==1.1.1

tools/third_party/html5lib/__init__.py

@@ -32,4 +32,4 @@
 
 # this has to be at the top level, see how setup.py parses this
 #: Distribution version number.
-__version__ = "1.2-dev"
+__version__ = "1.1"