opam admin list, allow to output the path to the selected opam packages

[dbuenzli]

I would like to have an output option that simply output the path to the opam file of the selected package. For example:

for f in $(opam admin list --latests-only --has-tag='org:erratique');
…

Somehow I worked around by deleting all the other packages via opam admin filter and then restoring them but it's a bit silly.

[kit-ty-kate]

As a quick workaround you can use the following which should work in all possible cases:

for f in $(opam admin list --latests-only --has-tag='org:erratique'); do
  f=$(find packages -path "packages/*/$f/opam" -print0)
  [...]
done