fix(esp_delta_ota): Fixed the esp_delta_ota_patch_gen script

Unable to get the validation hash due to breaking change in
esptool

Closes #605

Author: hrushikesh430

esp_delta_ota/examples/https_delta_ota/tools/esp_delta_ota_patch_gen.py

@@ -54,7 +54,7 @@ def create_patch(chip: str, base_binary: str, new_binary: str, patch_file_name:
         sys.stdout.close()
         sys.stdout = output
 
-    x = re.search(r"Validation Hash: ([A-Za-z0-9]+) \(valid\)", content)
+    x = re.search(r"Validation Hash: ([A-Za-z0-9]+) \(valid\)", content, re.IGNORECASE)
 
     if x is None:
         print("Failed to find validation hash in base binary.")