customParseFormat doesn't work reliably with a or A

[gr2m]

Describe the bug

Example

import dayjs from "dayjs";
import customParseFormat from "dayjs/plugin/customParseFormat.js";
dayjs.extend(customParseFormat);

console.log(
  dayjs("May 17, 2021 12:00pm", "MMMM D, YYYY H:mma", true).isValid()
);
// true

console.log(
  dayjs("May 17, 2021 1:00pm", "MMMM D, YYYY H:mma", true).isValid()
);
// false

I can paste the console.log statements into the developer tools console on https://day.js.org/ and get the same result.

Expected behavior

Parsing am/pm with a and AM/PM with A should set the hours offset as expected.

Information

• Day.js Version: 1.10.5
• OS: Mac OS X, Ubuntu Latest
• Browser: latest Firefox, Chrome
• Node: 14, 16
• Time zone: GMT-07:00 DST (Pacific Daylight Time)

[BePo65]

The problem is the comma in the date / format string; dayjs cannot handle this. PR #1913 should fix that