Update flatpak nightly products to 4.21 I-builds

Change-Id: Ib8da034160cd67df6a6b4ac29924cc4f4f988797
Signed-off-by: Mat Booth <mat.booth@gmail.com>
Reviewed-on: https://git.eclipse.org/r/c/linuxtools/org.eclipse.linuxtools.eclipse-build/+/181483
10 files changed