Upgrade to garage v0.8.0, plus a commit to fix panics

We were encountering panics (see
https://git.deuxfleurs.fr/Deuxfleurs/garage/issues/414). The new garage
commit is simply 0.8.0 plus the fix for that issue.

entrypoint/src/garage/admin_client.go

@@ -103,7 +103,7 @@ func (c *AdminClient) Do(
 
 	defer res.Body.Close()
 
-	if res.StatusCode != 200 {
+	if res.StatusCode >= 300 {
 		body, _ := io.ReadAll(res.Body)
 		return AdminClientError{
 			StatusCode: res.StatusCode,

nix/garage.nix

@@ -6,13 +6,13 @@
 
 }: let
 
-  version = "0.8.0-rc1";
+  version = "0.8.0-unstable";
 
   src = fetchgit {
     name = "garage-v${version}";
     url = "https://git.deuxfleurs.fr/Deuxfleurs/garage.git";
-    rev = "2197753dfdb25944e55c25d911ae6d14b8506c4d";
-    sha256 = "sha256-Rzwx1/vl3xg5bj4Chxj8VLBZ25zlPawOc+uMl3AHhkw=";
+    rev = "293139a94a8911aaac1b650e4707379a972196aa";
+    sha256 = "sha256-b6HHLnxMdmpngiywll6Egr8O9/4cqBN01Mj3OwVMeBc=";
   };
 
 in rec {