Enable ZIP 317 fees

Closes Electric-Coin-Company/zcash-swift-wallet-sdk#1186.

CHANGELOG.md

@@ -6,6 +6,13 @@ and this library adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
+## Changed
+
+### [#1186] Enable ZIP 317 fees
+- The SDK now generates transactions using [ZIP 317](https://zips.z.cash/zip-0317) fees,
+  instead of a fixed fee of 10,000 Zatoshi. Use `Proposal.totalFeeRequired` to check the
+  total fee for a transfer before creating it.
+
 ## Added
 
 ### [#1204] Expose APIs for working with transaction proposals

Sources/ZcashLightClientKit/Rust/ZcashRustBackend.swift

@@ -13,7 +13,7 @@ let globalDBLock = NSLock()
 
 actor ZcashRustBackend: ZcashRustBackendWelding {
     let minimumConfirmations: UInt32 = 10
-    let useZIP317Fees = false
+    let useZIP317Fees = true
 
     let dbData: (String, UInt)
     let fsBlockDbRoot: (String, UInt)