Merge pull request #5149 from danielgindi/release/5.1.0

Create 5.1.0 Release

Merge pull request #5028 from danielgindi/release/5.0.0

[WIP] Release/5.0.0

fix ios tests

Bump podsepc version

bump pod version

Merge pull request #4516 from StewartLynch/master

Add a video tutorial Link.md

Fix missing drawIconsEnabled parameter initialization in the copying …

…constructor of the ChartBaseDataSet (#4424)

Merge pull request #4399 from Rubenfer/master

Increase iOS version to 9 in Package.swift

1. update gem file. Using ruby-2.4.0 as minimum version for bundle up…

…date, as github_changelog_generator cannot be run on ruby-2.7.0(github-changelog-generator/github-changelog-generator#800), and ruby <2.4 will have openssl failures due to brew removed openssl@1.0 recently, this broke my Catalina machine.

2. update changelog

fix change log format