Add disclaimer in master about going to go-three

11 jobs for 104-typo-on-the-about-page in 54 seconds (queued for 2 seconds)
Name Stage Failure
failed
Go-py3.4 Test
Reading package lists...
Building dependency tree...
Reading state information...
Package libmysqlclient-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'libmysqlclient-dev' has no installation candidate
ERROR: Job failed: exit code 1
failed
Go-py3.5 Test
Reading package lists...
Building dependency tree...
Reading state information...
Package libmysqlclient-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'libmysqlclient-dev' has no installation candidate
ERROR: Job failed: exit code 1
failed
Go-py2.7 Test
Reading package lists...
Building dependency tree...
Reading state information...
Package libmysqlclient-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'libmysqlclient-dev' has no installation candidate
ERROR: Job failed: exit code 1