fix(ota): make update scripts self-updating and add cache-busting to installers

installer_refill.lua

@@ -54,19 +54,24 @@ local function httpGet(url)
   end
 end
 
+local function getCacheBustedUrl(url)
+  local sep = url:find("?") and "&" or "?"
+  return url .. sep .. "_t=" .. tostring(os.epoch and os.epoch("utc") or math.random(1, 999999))
+end
+
 term.clear()
 term.setCursorPos(1, 1)
 print("Refill Machine Installer")
 print("")
 print("Downloading refill machine program...")
 
-local ok, code = httpGet(URL_REFILL_MACHINE)
+local ok, code = httpGet(getCacheBustedUrl(URL_REFILL_MACHINE))
 if not ok or type(code) ~= "string" or #code == 0 then
   print("Download failed: " .. tostring(code or ""))
   return
 end
 
-local okUpdate, updateCode = httpGet(URL_UPDATE_REFILL)
+local okUpdate, updateCode = httpGet(getCacheBustedUrl(URL_UPDATE_REFILL))
 if not okUpdate or type(updateCode) ~= "string" or #updateCode == 0 then
   print("Download failed: " .. tostring(updateCode or ""))
   return