3.1.3

Version 3.1.3 brings the following updates:

• Migration to Xcode 12.5.
• CryptoSwift updated from 1.3.8 to 1.4.0 (https://github.com/krzyzanowskim/CryptoSwift/releases/tag/1.4.0).
• Two threading issues fixed (#350 with #351 and #352 with #353).
• A bug in the sample app fixed: refreshing Last Modified date after importing new mesh network configuration (f60f3b2).