bump Supervisor session storage versions

internal/fositestorage/authorizationcode/authorizationcode.go

@@ -36,7 +36,8 @@ const (
 	// Version 5 is when we added the UpstreamUsername and UpstreamGroups fields to psession.CustomSessionData.
 	// Version 6 is when we upgraded fosite in Dec 2023.
 	// Version 7 is when OIDCClients were given configurable ID token lifetimes.
-	authorizeCodeStorageVersion = "7"
+	// Version 8 is when GitHubIdentityProvider was added.
+	authorizeCodeStorageVersion = "8"
 )
 
 var _ oauth2.AuthorizeCodeStorage = &authorizeCodeStorage{}
@@ -397,5 +398,5 @@ const ExpectedAuthorizeCodeSessionJSONFromFuzzing = `{
 			"姧骦:駝重EȫʆɵʮGɃ"
 		]
 	},
-	"version": "7"
+	"version": "8"
 }`