docs: add Bounty Program Rules

BOUNTY_PROGRAM.md

@@ -178,6 +178,8 @@ In case a Bounty Issue gets an assignee before the End Of Life and is dropped af
 
 In case a Bounty Issue gets an assignee before the End Of Life and does not get completed within the assigned Timeline after the End Of Life due to Bounty Program Participant's misperformance, it gets the historical text label `bounty/misperformed` and is considered the one that reached End Of Life.
 
+In case a Bounty Issue gets an assignee before the End Of Life and during its technical resolution it becomes clear that this Bounty Issue cannot be completed due to unpredicted [force majeure](https://iccwbo.org/wp-content/uploads/sites/3/2020/03/icc-forcemajeure-hardship-clauses-march2020.pdf) and/or circumstances that could not be foreseen and/or that are beyond the control of both the Bounty Program Participant and the AsyncAPI Maintainer, it gets the historical text label `bounty/canceled` and is considered the one that reached End Of Life.
+
 Bounty Issue that reached End Of Life gets the historical text label `bounty/eol`, reward for this Bounty Issue gets excluded from the budget allocated for the corresponding calendar quarter round of the Bounty Program, and this Bounty Issue becomes a regular GitHub issue, which can be submitted again as a Bounty Issue Candidate.
 
 Dropped Bounty Issue can be assigned again to the same Bounty Program Participant who dropped it.