Cake v6.1.0 shipped: GitLab pipeline IDs, console colours, and dotnet fixes v6.1.0

43 issues closed, including a breaking change where GitLab's CI_PIPELINE_ID got too big for int (apparently GitLab's been counting way harder than expected). Also squashed bugs around console colourisation and DotNetSlnList hardcoding English like it's 1995. One minor breaking change, ngl, but your builds will thank you.