chore: v1.8.0, use variable font

NOTE: it seems that chrome cannot find local font when
`local()` is used with quoted font name.

Signed-off-by: Chawye Hsu <su+git@chawyehsu.com>

feat: overwrite gitako extension font family

Adjust z-index

Fix headers again

Fix #16

Fix sticky file headers

Bump version

Update header class

Fix new floating pr header

Fix header spacing and other issues