[Dune] Dune 2.7.0 Release Candidate 1 ready

[Christoph Grüninger]

Dear Dune users and developers,
Dune 2.7.0 Release Candidate 1 is ready! This means the core modules and
dune-uggrid, -typetree and -function. Please give them a try and do
whatever you do with regular releases. If you install them, please also
install RC 1. If you package them, please also package RC 1. If you use
your own modules, also use them together with RC 1.

Please report any bug you find!
If you did your tests and everything is fine, please drop me a line,
either on the mailing list or by private email. Otherwise I don't know
whether nobody did tests or whether there are no issues.
If you need back-ports from trunk, contact me.

You can use the Git tag v2.7.0rc1 or download the tarballs from
https://dune-project.org/download/2.7.0rc1/dune-common-2.7.0rc1.tar.gz
replace "common" by geometry, grid, grid-howto, localfunctions, and istl
to get all tarballs.
With an appended .asc you get the PGP signature files for the tarballs.
For uggrid, typetree, and functions there are no tarballs.

Bye
Christoph