devel/libical: update to 3.0.8

Changelog since 3.0.4 (2018-08-14) to 3.0.8 (2020-03-07):

3.0.5:

• New publicly available function: 1 icalproperty_get_datetime_with_component()
• Allow reset DATE/DATE-TIME VALUE parameter for all-day events
• icalproperty_get_datetime_with_component() will use location as TZID fallback.
• New CMake option ENABLE_GTK_DOC for disabling the libical-glib developer documentation
• GObject Introspection - use $MAJOR-0 versioning
• libical-glib API is considered unstable: define LIBICAL_GLIB_UNSTABLE_API=1 before including <libical-glib/libical-glib.h>
• Built-in timezones updated to tzdata2019a
• De-fuzzifications and Coverity fixes

3.0.6:

• Handle both COUNT and UNTIL in RRULEs
• Fix RRULE BYDAY with INTERVAL=2 conflict
• Various fuzzification fixes
• New publicly available function: icaltimezone_truncate_vtimezone()
• Add option to disable building the test suite
• Built-in timezones updated to tzdata2019c

3.0.7:

• libical-glib: Fix ICalAttach handling of the icalattach native structure
• Let icalattach_new_from_data() use the 'free_fn' argument again
• Fix memory leaks in attachment handling and elsewhere
• Fix a multithreading race condition
• More fuzzification fixes

3.0.8:

• Fix for icalattach_new_from_data() and the 'free_fn' argument
• Fix if recurrencetype contains both COUNT and UNTIL (only output UNTIL in the RRULE)