sys-apps/portage: Bump to version 2.3.88

sys-apps/portage: Bump to version 2.3.88

 #649622 prevent unecessary installation of virtual/w3m followed
         by removal by depclean
 #705736 preserve-libs: prevent unecessary preservation of system
         libraries which a package bundles
 #707820 generate API documentation with sphinx-apidoc
 #708448 support FEATURES=qa-unresolved-soname-deps so that the
         QA warning from bug 704320 can be disabled
 #708660 phase-helpers.sh: avoid passing an empty root value to
         portageq when ebuild IPC is disabled

Bug: https://bugs.gentoo.org/706142
Bug: https://bugs.gentoo.org/649622
Bug: https://bugs.gentoo.org/705736
Bug: https://bugs.gentoo.org/707820
Bug: https://bugs.gentoo.org/708448
Bug: https://bugs.gentoo.org/708660
Package-Manager: Portage-2.3.88, Repoman-2.3.20
Signed-off-by: Zac Medico <zmedico@gentoo.org>