dockerfile 0.2.0 to 0.3.0

• fix: graceful failing in case no internet

• feat: Added dock_from_renv(), to create a Dockerfile from a renv.lock file (@JosiahParry, @statnmap)

dockerfiler 0.1.4

• new version of dock_from_desc()

dockerfiler 0.1.3.9000

• Corrected bug in rthis()

dockerfiler 0.1.3

• Added the add_after() R6 method
• Added dock_from_desc(), to create a Dockerfile from a DESCRIPTION