amp-stream-gallery v0.1 appears on amp.dev but it is invalid

## 🐛 Bug Report

### Current behavior

For `amp-stream-gallery`, two versions are offered: 0.1 and 1.0. However, only [1.0 appears](https://github.com/ampproject/amphtml/blob/e3abe630d3e0bcce78115e0b51d5da776e427904/extensions/amp-stream-gallery/validator-amp-stream-gallery.protoascii#L22-L23) in the validator spec.

See https://amp.dev/documentation/components/amp-stream-gallery-v0.1/?format=websites

See invalid/broken 0.1 in [playground example](https://playground.amp.dev/#share=PCFET0NUWVBFIGh0bWw+CjxodG1sIOKaoT4KPGhlYWQ+CiAgPG1ldGEgY2hhcnNldD0idXRmLTgiIC8+CiAgPHRpdGxlPk15IEFNUCBQYWdlPC90aXRsZT4KICA8bGluayByZWw9ImNhbm9uaWNhbCIgaHJlZj0ic2VsZi5odG1sIiAvPgogIDxtZXRhIG5hbWU9InZpZXdwb3J0IiBjb250ZW50PSJ3aWR0aD1kZXZpY2Utd2lkdGgiIC8+CiAgPHN0eWxlIGFtcC1ib2lsZXJwbGF0ZT5ib2R5ey13ZWJraXQtYW5pbWF0aW9uOi1hbXAtc3RhcnQgOHMgc3RlcHMoMSxlbmQpIDBzIDEgbm9ybWFsIGJvdGg7LW1vei1hbmltYXRpb246LWFtcC1zdGFydCA4cyBzdGVwcygxLGVuZCkgMHMgMSBub3JtYWwgYm90aDstbXMtYW5pbWF0aW9uOi1hbXAtc3RhcnQgOHMgc3RlcHMoMSxlbmQpIDBzIDEgbm9ybWFsIGJvdGg7YW5pbWF0aW9uOi1hbXAtc3RhcnQgOHMgc3RlcHMoMSxlbmQpIDBzIDEgbm9ybWFsIGJvdGh9QC13ZWJraXQta2V5ZnJhbWVzIC1hbXAtc3RhcnR7ZnJvbXt2aXNpYmlsaXR5OmhpZGRlbn10b3t2aXNpYmlsaXR5OnZpc2libGV9fUAtbW96LWtleWZyYW1lcyAtYW1wLXN0YXJ0e2Zyb217dmlzaWJpbGl0eTpoaWRkZW59dG97dmlzaWJpbGl0eTp2aXNpYmxlfX1ALW1zLWtleWZyYW1lcyAtYW1wLXN0YXJ0e2Zyb217dmlzaWJpbGl0eTpoaWRkZW59dG97dmlzaWJpbGl0eTp2aXNpYmxlfX1ALW8ta2V5ZnJhbWVzIC1hbXAtc3RhcnR7ZnJvbXt2aXNpYmlsaXR5OmhpZGRlbn10b3t2aXNpYmlsaXR5OnZpc2libGV9fUBrZXlmcmFtZXMgLWFtcC1zdGFydHtmcm9te3Zpc2liaWxpdHk6aGlkZGVufXRve3Zpc2liaWxpdHk6dmlzaWJsZX19PC9zdHlsZT48bm9zY3JpcHQ+PHN0eWxlIGFtcC1ib2lsZXJwbGF0ZT5ib2R5ey13ZWJraXQtYW5pbWF0aW9uOm5vbmU7LW1vei1hbmltYXRpb246bm9uZTstbXMtYW5pbWF0aW9uOm5vbmU7YW5pbWF0aW9uOm5vbmV9PC9zdHlsZT48L25vc2NyaXB0PgogIDxzY3JpcHQgYXN5bmMgc3JjPSJodHRwczovL2Nkbi5hbXBwcm9qZWN0Lm9yZy92MC5qcyI+PC9zY3JpcHQ+CiAgPHNjcmlwdCBhc3luYyBjdXN0b20tZWxlbWVudD0iYW1wLXN0cmVhbS1nYWxsZXJ5IiBzcmM9Imh0dHBzOi8vY2RuLmFtcHByb2plY3Qub3JnL3YwL2FtcC1zdHJlYW0tZ2FsbGVyeS0wLjEuanMiPjwvc2NyaXB0PgogIDxzdHlsZSBhbXAtY3VzdG9tPgogICAgICBoMSB7CiAgICAgICAgbWFyZ2luOiAxcmVtOwogICAgICB9CiAgICA8L3N0eWxlPgo8L2hlYWQ+Cjxib2R5PgogIDxhbXAtc3RyZWFtLWdhbGxlcnkgd2lkdGg9IjcuNSIgaGVpZ2h0PSIyIiBsYXlvdXQ9InJlc3BvbnNpdmUiPgogICAgPGFtcC1pbWcgc3JjPSJpbWcxLnBuZyIgbGF5b3V0PSJmbGV4LWl0ZW0iPjwvYW1wLWltZz4KICAgIDxhbXAtaW1nIHNyYz0iaW1nMi5wbmciIGxheW91dD0iZmxleC1pdGVtIj48L2FtcC1pbWc+CiAgICA8YW1wLWltZyBzcmM9ImltZzMucG5nIiBsYXlvdXQ9ImZsZXgtaXRlbSI+PC9hbXAtaW1nPgogICAgPGFtcC1pbWcgc3JjPSJpbWc0LnBuZyIgbGF5b3V0PSJmbGV4LWl0ZW0iPjwvYW1wLWltZz4KICAgIDxhbXAtaW1nIHNyYz0iaW1nNS5wbmciIGxheW91dD0iZmxleC1pdGVtIj48L2FtcC1pbWc+CiAgICA8YW1wLWltZyBzcmM9ImltZzYucG5nIiBsYXlvdXQ9ImZsZXgtaXRlbSI+PC9hbXAtaW1nPgogICAgPGFtcC1pbWcgc3JjPSJpbWc3LnBuZyIgbGF5b3V0PSJmbGV4LWl0ZW0iPjwvYW1wLWltZz4KICA8L2FtcC1zdHJlYW0tZ2FsbGVyeT4KPC9ib2R5Pgo8L2h0bWw+).

### Expected behavior/code

No docs should be generated for 0.1.