Update docker/dockerfile Docker tag to v1.21 (#1017)

renovate[bot] · web-flow · commit e01a674ebedb · 2026-01-22T10:25:42.000Z
| datasource | package           | from | to   |
| ---------- | ----------------- | ---- | ---- |
| docker     | docker/dockerfile | 1.20 | 1.21 |

Signed-off-by: renovate[bot] &lt;29139614+renovate[bot]@users.noreply.github.com&gt;
Co-authored-by: renovate[bot] &lt;29139614+renovate[bot]@users.noreply.github.com&gt;
diff --git a/Dockerfile b/Dockerfile
@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile:1.20
+# syntax=docker/dockerfile:1.21
 ARG BUILD_OS=debian
 FROM --platform=$BUILDPLATFORM tonistiigi/xx:1.9.0 AS xx
 

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-# syntax=docker/dockerfile:1.20`
	`1`	`+# syntax=docker/dockerfile:1.21`
`2`	`2`	`ARG BUILD_OS=debian`
`3`	`3`	`FROM --platform=$BUILDPLATFORM tonistiigi/xx:1.9.0 AS xx`
`4`	`4`