Merge pull request ChartsOrg#5028 from danielgindi/release/5.0.0

[WIP] Release/5.0.0

fix ios tests

Bump podsepc version

bump pod version

Merge pull request ChartsOrg#4516 from StewartLynch/master

Add a video tutorial Link.md

Fix missing drawIconsEnabled parameter initialization in the copying …

…constructor of the ChartBaseDataSet (ChartsOrg#4424)

Merge pull request ChartsOrg#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 [email protected] recently, this broke my Catalina machine.

2. update changelog

fix change log format

correct 3.3 to 3.3.0.