component/depot_tools: fix typo on revision

as a result, this checkout was not pinned and software was not
reproducible

component/depot_tools/buildout.cfg

@@ -7,5 +7,5 @@ parts =
 [depot_tools]
 recipe = slapos.recipe.build:gitclone
 repository = https://chromium.googlesource.com/chromium/tools/depot_tools.git
-revsion = e023d4482012d89690f6a483e877eceb47c4501e
+revision = e023d4482012d89690f6a483e877eceb47c4501e
 git-executable = ${git:location}/bin/git