Feature request: year.quarter option for `date_style` in `fmt_date()`

[eroten]

Prework

• Read and abide by gt's code of conduct and contributing guidelines.
• Search for duplicates among the existing issues (both open and closed).

Proposal

Similar to #1028, I would appreciate a date formatting option for year and quarter, like lubridate::quarter().

library(lubridate, warn.conflicts = F)

quarter(today(), type = "year.quarter")
#> [1] 2022.3

^{Created on 2022-09-09 with reprex v2.0.2}

"y_q" : "2022.3"

[rich-iannone]

Perfect timing! Adding new date/time/datetime features in #1053 and I will sneak this feature request in there!