Updating images for legacy pricing for uptime (#12680)

Author: codyde

docs/pricing/img/on-demand-budgets.png

@@ -31,7 +31,7 @@ If you run out of **both** your prepaid and on-demand volume, any new data you s
 
 ### Per-Category Pricing
 
-If you'd like to buy either prepaid or on-demand data on top of what's included in your plan, you can buy as much as you think you'll need per data category. [Errors](#errors-pricing), [Performance](#performance-pricing), [Replays](#replays-pricing), [Cron Monitors](#cron-monitors-pricing), and [Attachments](#attachments-pricing) each have their own unique pricing structures, as listed in the tables below:
+If you'd like to buy either prepaid or on-demand data on top of what's included in your plan, you can buy as much as you think you'll need per data category. [Errors](#errors-pricing), [Performance](#performance-pricing), [Replays](#replays-pricing), [Cron Monitors](#cron-monitors-pricing), [Uptime Monitors](#uptime-monitors-pricing), and [Attachments](#attachments-pricing) each have their own unique pricing structures, as listed in the tables below:
 
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