dev: cleanup dependencies

* blog/blog.cabal: remove some explicit dependency version constraints
  which are handled implicitly by the dependency on yesod-platform
dev: update yesod-test dependency
ruby: use https to fetch ruby gems to avoid warning
dev: mTag -> µtag in haskell code

* blog/Handler/Home.hs (renderEntries): remove name-collision to
  acquiesce travis-ci