Pending Intent can have one of FLAG_IMMUTABLE or FLAG_MUTABLE

[usmanabid09]

Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.
Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.

[cortinico]

We already do have this support:

chucker/library/src/main/kotlin/com/chuckerteam/chucker/internal/support/NotificationHelper.kt

Lines 135 to 139 in 28353fa

	private fun immutableFlag() = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
	PendingIntent.FLAG_IMMUTABLE
	} else {
	0
	}

It was done in this PR:

• Add immutable flag to pending intents #593