Preparation for Release 6.2.0

[slaff]

This issue is created to collect all the tasks we need to do before the 6.2 release.

Source Code

• Update Sming/Core/SmingVersion.h.
• Update Readme.md.
• Merge develop into master.
• Tag the source code in the master branch.
• Add upgrade document

New features

Improvements

• Fix build errors in MacOS (jerryscript) #2974
• Pull OneWire 2.3.8 from Paul Stoffregen's upstream  #2981

Bug fixes

• Basic_Tasks sample gets watchdog resets on esp32 #2975
• Fix Esp32 issue with Sming tasks not getting handled at startup #2972
• Fix esp32 tcpip message starvation when task queue stressed #2976

Changes

Deprecations

Breaking Changes

Security

All PRs scheduled for this release can be seen from here