file upload performance improvement

• fixed #251
• file upload performance improvement

persist curl connection handle.

• persist curl resource handle(see #241 )
• new .env variable : JIRA_LOG_ENABLED for no logging(see #239, #242)

DotEnv 3.x support for laravel 5.8

• PHP Dotenv v3 support(#234)
• Use Proxy Configuration for curl handle(#231 )

use LoggerInterface in other services.

see #229

Change JIRAClient Constructor param to PSR-3 's LoggerInterface.

see #225

fixed curl exec failure when passed http parameter type is array.

see #221

fixed json mapping failed on DateTimeInterface field

see #212 #216

Use DateTimeInterface instead of DateTime

• Use DateTimeInterface instead of DateTime(see #212)
• Updated documentation(see #213 )

[NEW] some new functionality for Version

add new functionality for Version

• See #202 , #203, #204

add laravel package auto discover support

• See #205

[NEW] create project function.

see #195