Virtualenv 20.26.6 Breaks Virtualenv-Tool Relocation

[tcjennings]

The virtualenv 20.26.6 release includes a breaking change for virtualenv-tools3; the --update-path command fails because the new activation script includes neither case being checked, i.e., the value is no longer quoted.

i.e.,

for possible in ('VIRTUAL_ENV="', "VIRTUAL_ENV='"):

should now include an unquoted option:

for possible in ('VIRTUAL_ENV="', "VIRTUAL_ENV='", "VIRTUAL_ENV="):

Ref: pypa/virtualenv@86ddded#diff-527affb817020f216260af82eb30477ed59060da3f11312f476657974f8b515aL48