Use int64 instead of uint64

uint64 isn't a valid swagger format.
https://swagger.io/specification/v2/#dataTypeFormat

Makefile

@@ -50,6 +50,7 @@ embed-static:
 
 update-swagger:
 	swagger generate spec --scan-models -o docs/spec.json
+	sed -i 's/"uint64"/"int64"/g' docs/spec.json
 
 check-swagger: update-swagger
 ## add the docs to git, this changes line endings in git, otherwise this does not work on windows

docs/spec.json

@@ -1894,7 +1894,7 @@
         "id": {
           "description": "The application id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 5
@@ -1942,7 +1942,7 @@
         "id": {
           "description": "The client id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 5
@@ -2033,7 +2033,7 @@
         "appid": {
           "description": "The application id that send this message.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ApplicationID",
           "readOnly": true,
           "example": 5
@@ -2065,7 +2065,7 @@
         "id": {
           "description": "The message id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 25
@@ -2147,7 +2147,7 @@
         "since": {
           "description": "The ID of the last message returned in the current request. Use this as alternative to the next link.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "minimum": 0,
           "x-go-name": "Since",
           "readOnly": true,
@@ -2205,7 +2205,7 @@
         "id": {
           "description": "The plugin id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 25
@@ -2266,7 +2266,7 @@
         "id": {
           "description": "The user id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 25
@@ -2318,7 +2318,7 @@
         "id": {
           "description": "The user id.",
           "type": "integer",
-          "format": "uint64",
+          "format": "int64",
           "x-go-name": "ID",
           "readOnly": true,
           "example": 25