Update mimerl dependency to ~>1.1 to let clients use the newer mimerl types

[monkeydom]

Currently hackney requires 1.0.3 which disallows clients to use a newer version of mimerl themselves without overriding the dependency management.

[oladipo]

looks like there is a typo in the rebar.config file line 25.

The mimerl dependency is listed in a mix dependency format:

     {mimerl, "~>1.1"},

instead of

     {mimerl, "1.1"}

[aboroska]

@oladipo Note that recent rebar3 versions do support the semver format: {mimerl, "~> 1.1"},

[oladipo]

Thanks @aboroska