Allow the treasury to have a maximum bound on the bond (#10689)

* Allow the treasury to have a maximum bound on the bond

* Update frame/treasury/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

substrate/bin/node/runtime/src/lib.rs

@@ -880,6 +880,7 @@ impl pallet_treasury::Config for Runtime {
 	type OnSlash = ();
 	type ProposalBond = ProposalBond;
 	type ProposalBondMinimum = ProposalBondMinimum;
+	type ProposalBondMaximum = ();
 	type SpendPeriod = SpendPeriod;
 	type Burn = Burn;
 	type BurnDestination = ();