Add README regarding the master branch and the future of this repo

2 jobs for master in 36 minutes and 6 seconds (queued for 130 minutes and 29 seconds)
Status Job ID Name Coverage
  Build
failed #67376
build_clazy_clang_tidy

00:16:30

failed #67375
linux kf5-qt5 qt5.12

00:19:36

 
Name Stage Failure
failed
build_clazy_clang_tidy Build
-- Build files have been written to: /builds/pim/kdepim-apps-libs/build
$ python3 -u $CI_TOOLING/helpers/compile-build.py --product $PRODUCT --project $PROJECT --branchGroup $BRANCH_GROUP --platform $PLATFORM --usingInstall $INSTALL_PREFIX
$ cd build && run-clang-tidy
Error: could not find compilation database.
Uploading artifacts for failed job
Uploading artifacts...
WARNING: JUnitTestResults.xml: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1
failed
linux kf5-qt5 qt5.12 Build
-- Build files have been written to: /builds/pim/kdepim-apps-libs/build
$ python3 -u $CI_TOOLING/helpers/compile-build.py --product $PRODUCT --project $PROJECT --branchGroup $BRANCH_GROUP --platform $PLATFORM --usingInstall $INSTALL_PREFIX
$ python3 -u $CI_TOOLING/helpers/install-build.py --product $PRODUCT --project $PROJECT --branchGroup $BRANCH_GROUP --platform $PLATFORM --installTo $INSTALL_PREFIX
make: *** No rule to make target 'install'. Stop.
Uploading artifacts for failed job
Uploading artifacts...
WARNING: JUnitTestResults.xml: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1