wendelin.core: v↑ 2.0.alpha2.post2 -> 2.0.alpha3

New WC2 alpha release provides us with various small fixes:

    nexedi/wendelin.core@5e5ad598...7ce0978d

It also prepares upgrading SlapOS go default version to v1.18
(WC2 alpha2 doesn't work with go1.18).

component/wendelin.core/buildout.cfg

@@ -50,7 +50,7 @@ CGO_LDFLAGS += -Wl,-rpath=${zlib:location}/lib
 recipe  = slapos.recipe.build:gitclone
 repository = https://lab.nexedi.com/nexedi/wendelin.core.git
 branch   = master
-revision = wendelin.core-2.0.alpha2-2-g3d0f134c
+revision = wendelin.core-2.0.alpha3
 # dir is pretty name as top-level recipe
 location = ${buildout:parts-directory}/wendelin.core
 git-executable = ${git:location}/bin/git