upload-plugin-from-maven: use newer imagej-maven-plugin

The old version copied all test-scoped artifacts, too...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
upload-plugin-from-maven: simplify call to imagej-maven-plugin

No need to specify groupId, artifactId and version separately...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
upload-plugin-from-maven: use edit-update-site all the time

The updater is more forgiving (for a couple of days now), so let's use
edit-update-site instead of trying to figure out whether we have to call
add-update-site instead.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
upload-plugin-from-maven: recommend using $HOME/.netrc

It is much safer to use the .netrc file instead of hard-coding the
password in the db.xml.gz file. The only downside is that you cannot use
spaces, tabs or newlines in your password, but this developer says: just
don't use them, then.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'dev-update-sites'

This merge branch updates the script to upload dev update sites (such
as TrackMate-dev) to behave a *little* more cleverly.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>