[cibuild.sh] Use env bash for the shebang
[cibuild.sh] Use env bash for the shebang

It's best practice to use #!/usr/bin/env bash, rather
than #!/bin/bash, as on some systems bash may not always
be in /bin. See StackOverflow: http://stackoverflow.com/a/21613044/4077294

chipitsine/msbuild,chipitsine/msbuild,AndyGerlicher/msbuild,mono/msbuild,chipitsine/msbuild,jeffkl/msbuild,AndyGerlicher/msbuild,cdmihai/msbuild,jeffkl/msbuild,sean-gilliam/msbuild,rainersigwald/msbuild,mono/msbuild,Microsoft/msbuild,sean-gilliam/msbuild,rainersigwald/msbuild,cdmihai/msbuild,mono/msbuild,Microsoft/msbuild,cdmihai/msbuild,sean-gilliam/msbuild,sean-gilliam/msbuild,cdmihai/msbuild,chipitsine/msbuild,Microsoft/msbuild,rainersigwald/msbuild,jeffkl/msbuild,AndyGerlicher/msbuild,AndyGerlicher/msbuild,Microsoft/msbuild,jeffkl/msbuild,mono/msbuild,rainersigwald/msbuild