Daylight saving time correction

Take SIGMOD as an example,

RESEARCH PAPER SUBMISSION CYCLE A (All Deadlines are 11:59 PM Pacific Time)

should be UTC-7, the webpage shows UTC-8

"Thanks for your constructive suggestions, we will consider add some logic to resolve this problem, thank you!" ---- @jacklightChen

Yeah, this feature sounds very important, thanks for your kind advice! We may fix it later this month, and of course sending a pr is also highly welcomed~

We now require ddl to be checked whether it is during daylight time before merge. An example of modification: https://github.com/ccfddl/ccf-deadlines/pull/190.