www/py-soupsieve: update to 2.7

Port changes:

• switch to USE_PYTHON=pep517
• switch to USE_PYTHON=pytest and remove do-test target
• switch lxml dependency to devel/py-lxml5 (from devel/py-lxml)

Upstream changes:

• https://github.com/facelessuser/soupsieve/releases/tag/2.1.0
• https://github.com/facelessuser/soupsieve/releases/tag/2.2
• https://github.com/facelessuser/soupsieve/releases/tag/2.2.1
• https://github.com/facelessuser/soupsieve/releases/tag/2.3
• https://github.com/facelessuser/soupsieve/releases/tag/2.3.1
• https://github.com/facelessuser/soupsieve/releases/tag/2.3.2
• https://github.com/facelessuser/soupsieve/releases/tag/2.3.2.post1
• https://github.com/facelessuser/soupsieve/releases/tag/2.4
• https://github.com/facelessuser/soupsieve/releases/tag/2.4.1
• https://github.com/facelessuser/soupsieve/releases/tag/2.5
• https://github.com/facelessuser/soupsieve/releases/tag/2.6
• https://github.com/facelessuser/soupsieve/releases/tag/2.7

PR: 288048
Approved by: wen (maintainer)