net-mgmt/netbox: Update to 2.7.7

• Remove the "post-patch" target because the "requirements.txt" is only used for installations via devel/py-pip.

Notable changes since 2.6.12:

• Bulk import of device components via CSV files
• External file storage support (FTP, S3, SFTP, etc.)
• Rack elevations rendered by SVG (= Scalable Vector Graphics)
• Separate configuration for Webhooks and Cache databases via Redis
• Add ability to clone objects (pre-populate form fields)
• Toggle config context display between JSON and YAML
• Add support for Redis Sentinel
• Further cable and port types
• Many other enhancements and bugfixes

https://github.com/netbox-community/netbox/blob/v2.7.7/docs/release-notes/version-2.7.md