bump to 1.21 (#20)

closes #18

FloatMS (#17)

implements #15

Fix CI (#13)

switched from github.com/pkg/errors to built-in errors (#11)

goreportcard (#10)

* typo fixed

* added goreportcard

Add linter (#7)

* added linter

* disable tests

* more linters

* check linter

* nl

* more linters

* multiline

* removed not found

* goimports

* wsl

renaming

renamed

Add StrSeconds and StrMilliseconds (#4)

* go mod

* added parseInt64

* added StrSeconds

* updated Readme

* more examples

* added msToTime()

* used parseInt64()

* docstring

* added StrMilliseconds

* bumped deps

* better errors

Add example (#3)

* added example

* made test from example

* removed redundant

* removed redundant from docstring

* renamed