rough early draft of a proposal for podping tag

proposal-docs/podping/podping.md

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+# The "podcast:podping" Sepcification
+
+<small>Version 1.0 by Brian of London - 2021.06.08</small>
+
+<br>
+
+## Purpose
+
+The Podping notification system is rapidly developing as a new standard for signalling new episodes of podcasts to reduce constant polling. Once a new episode or entirely new podcast is sent out as a podping on the Hive blockchain, aggregators and apps can query the feed.
+
+However, as pointed out in issue https://github.com/Podcastindex-org/podcast-namespace/issues/258, there is, as yet, no way to know which feeds are using Podping.
+
+This tag proposal will allow feed owners and the hosts of multiple feeds, to signal that future updates will be sent via Podping and there is no need to speculatively poll this rss feed.
+
+An additional benefit will derive if feeds signal the name or names of the Hive accounts authorized to send Podpings. These authorized Hive accounts will be included in a `<podcast:podpingAuth>` tag
+
+## Specification
+
+For the `<podcast:podping>` tag there are no attributes.
+
+For the optional but helpful `<podcast:podpingAuth>` tag there is one attribute, a single value with a single allowed Hive account.
+
+## Example
+
+```xml
+<podcast:podping>
+    <podcast:podpingAuth account="hivehydra"/>
+    <podcast:podpingAuth account="hive-hydra"/>
+</podcast:podping>
+```