fix: Fix exception when updating via binary.

Attempting to update Gitea using the binary mode results in an exception
because `isTool` did not have a `self` parameter. This fixes the issue,
allowing binary updates.

gitea_auto_update/lib/download.py

@@ -28,7 +28,7 @@ class Download:
         self.downloadGiteaFiles()
         self.checkAndExtract()
 
-    def isTool(name):
+    def isTool(self, name):
         # Function to check if tool is available
         ##Check whether `name` is on PATH and marked as executable.
         return which(name) is not None