add pull option to rebuild so that it always pulls latest version

.install/bin/pdm-build

@@ -87,7 +87,7 @@ if [[ $opt_squash -eq 1 ]]; then
     buildopts="$buildopts --squash-all"
 fi
 if [[ $opt_redo -eq 1 ]]; then
-    buildopts="$buildopts --no-cache"
+    buildopts="$buildopts --no-cache --pull"
 fi
 
 # tell buildah to build images in docker format instead of the default OCI format