Update releases branch with changes from 19/06 discussion

• set the correct mpsd spack branch
• use gcc in general and not a specific version as system compiler

changed title from Update releases branch with correct spack branch to Update releases branch with changes from 19/06 discussion

changed the description

added 1 commit

• 42243903 - use gcc in general instead of a specific version

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Checking for build at http://mpsd-kartoffel.desy.de:8010/#/builders/14/builds/105

mentioned in merge request mpsd-software-manager!74 (merged)

The toolchains and octopus gets built in the CI so I mark this as mergable

requested review from @hans.fangohr

approved this merge request

mentioned in commit 47dde834

merged

mentioned in issue #33 (closed)

mentioned in issue #32 (closed)