Add support for network-3.0.0.0

[naushadh]

Changes

• Relax network upper bound to fix network 3.0.0.0 commercialhaskell/stackage#4312
• Address test failures in a backward compatible manner by conditionally switching to newer APIs suggested by network-2.7.0 docs for Network.Socket.
• Bumped changelog and cabal

CI

• Looks like Travis isn't enabled here yet; however the following shows Travis run results on the fork: https://travis-ci.com/naushadh/io-streams/builds/97970263
• Failures appear to be unrelated to the incoming change, caused by an existing cabal flag:

$ (cd io-streams-* && cabal check)
Warning: These warnings may cause trouble when distributing the package:
Warning: 'ghc-options/ghc-prof-options: -fprof*' profiling flags are typically
not appropriate for a distributed library package. These flags are useful to
profile this package, but when profiling other packages that use this one
these flags clutter the profile output with excessive detail. If you think
other packages really want to see cost centres from this package then use
'-fprof-auto-exported' which puts cost centres only on exported functions.
Alternatively, if you want to use this, make it conditional based on a Cabal
configuration flag (with 'manual: True' and 'default: False') and enable that
flag during development.
Warning: 'ghc-options/ghc-prof-options: -fprof*' profiling flags are typically
not appropriate for a distributed library package. These flags are useful to
profile this package, but when profiling other packages that use this one
these flags clutter the profile output with excessive detail. If you think
other packages really want to see cost centres from this package then use
'-fprof-auto-exported' which puts cost centres only on exported functions.
Alternatively, if you want to use this, make it conditional based on a Cabal
configuration flag (with 'manual: True' and 'default: False') and enable that
flag during development.
The command "(cd io-streams-* && cabal check)" exited with 1.

[hvr]

Renamed cause this PR is a lot more than merely relaxing a version bound... ;-)

[gregorycollins]

By PVP this has to be a minor version bump, but I'll fix it post-facto