Update opam images hashes

example.spec

@@ -1,4 +1,4 @@
-; This script builds OBuilder itself using a snapshot of the ocaml/opam:debian-11-ocaml-4.14 base image.
+; This script builds OBuilder itself using a snapshot of the ocaml/opam:debian-12-ocaml-4.14 base image.
 ;
 ; Run it from the top-level of the OBuilder source tree, e.g.
 ;
@@ -7,11 +7,11 @@
 ; The result can then be found in /tank/HASH/rootfs/ (where HASH is displayed at the end of the build).
 
 ((build dev
-	((from ocaml/opam@sha256:4bfe3c0814b4220417d6ccbbed7eb5486a35d900024745c1f299973e9584e0e5)
+	((from ocaml/opam@sha256:02f01da51f1ed2ae4191f143a46a508e2a34652c11ad2715e2bbe8e0d36fc30d)
 	 (workdir /src)
 	 (user (uid 1000) (gid 1000))                           ; Build as the "opam" user
 	 (run (shell "sudo chown opam /src"))
-	 (env OPAM_HASH "f44d347b2119b4bdfddfb2a8ec55ae25c396c0d7")
+	 (env OPAM_HASH "8187cd8d3681d53f5042b5da316fa3f5e005a247")
 	 (run
 	  (network host)
 	  (shell "sudo apt-get --allow-releaseinfo-change update"))

example.windows.spec

@@ -1,5 +1,5 @@
 ; This script builds OBuilder itself using a snapshot of the
-; ocaml/opam:windows-mingw-ltsc2022-ocaml-4.14 base image.
+; ocaml/opam:windows-server-mingw-ltsc2022-ocaml-4.14 base image.
 ;
 ; Run it from the top-level of the OBuilder source tree, e.g.
 ;
@@ -12,7 +12,7 @@
 ; ROOTID is computed as follows: $(realpath "$(root)" | sha256sum | cut -b -7)
 
 ((build dev
-	((from ocaml/opam@sha256:4bfe3c0814b4220417d6ccbbed7eb5486a35d900024745c1f299973e9584e0e5)
+	((from ocaml/opam@sha256:cdd6e6604489d7700af2768f939439593c5c2f5e6585db8827297ec02d1113ef)
 	 (workdir /src)
 	 (env OPAM_REPO_MINGW_HASH "921b0eceb594f96c0c7f40bb2676783be4362aeb") ; Fix the version of opam-repository-mingw we want
 	 (env OPAM_HASH "f44d347b2119b4bdfddfb2a8ec55ae25c396c0d7") ; Fix the version of opam-repository we want