chore: Use containers/ directory as contextual for container builds

xtask/src/containers.rs

@@ -89,7 +89,7 @@ pub fn build_container_image(args: BuildContainerImageArgs) -> anyhow::Result<()
             for tag in tags.iter() {
                 cmd.args([OsStr::new("-t"), tag]);
             }
-            cmd.args([OsStr::new("-f"), &dockerfile, OsStr::new(".")])
+            cmd.args([OsStr::new("-f"), &dockerfile, OsStr::new("containers/")])
                 .stdout(Stdio::inherit())
                 .stderr(Stdio::inherit());
             if no_cache {