[SPARK-32866][K8S] Fix docker cross-build
[SPARK-32866][K8S] Fix docker cross-build

### What changes were proposed in this pull request?

Add `--push` to the docker script for buildx

### Why are the changes needed?

Doing a separate docker push with `buildx` images doesn't work.

### Does this PR introduce _any_ user-facing change?

Automatically pushes work when cross-building.

### How was this patch tested?

cross-built docker containers

Closes #31299 from holdenk/SPARK-32866-docker-buildx-update.

Authored-by: Holden Karau <7ba12a55c808179d9faba67213e9e2d6eda985f0@apple.com>
Signed-off-by: Holden Karau <7ba12a55c808179d9faba67213e9e2d6eda985f0@apple.com>

WeichenXu123/spark,hvanhovell/spark,mahak/spark,zzcclp/spark,zzcclp/spark,dongjoon-hyun/spark,JoshRosen/spark,BryanCutler/spark,hvanhovell/spark,BryanCutler/spark,maropu/spark,cloud-fan/spark,shaneknapp/spark,ueshin/apache-spark,zzcclp/spark,holdenk/spark,apache/spark,vinodkc/spark,nchammas/spark,nchammas/spark,JoshRosen/spark,taroplus/spark,witgo/spark,WeichenXu123/spark,wangyum/spark,jiangxb1987/spark,milliman/spark,chuckchen/spark,shaneknapp/spark,vinodkc/spark,holdenk/spark,xuanyuanking/spark,dongjoon-hyun/spark,milliman/spark,wangmiao1981/spark,vinodkc/spark,witgo/spark,rednaxelafx/apache-spark,wangmiao1981/spark,milliman/spark,apache/spark,jiangxb1987/spark,maropu/spark,xuanyuanking/spark,srowen/spark,witgo/spark,WeichenXu123/spark,apache/spark,taroplus/spark,apache/spark,witgo/spark,wangmiao1981/spark,JoshRosen/spark,shaneknapp/spark,hvanhovell/spark,nchammas/spark,ueshin/apache-spark,HyukjinKwon/spark,milliman/spark,mahak/spark,xuanyuanking/spark,cloud-fan/spark,ueshin/apache-spark,taroplus/spark,JoshRosen/spark,WeichenXu123/spark,WeichenXu123/spark,nchammas/spark,apache/spark,zzcclp/spark,wangyum/spark,nchammas/spark,jiangxb1987/spark,BryanCutler/spark,zero323/spark,chuckchen/spark,witgo/spark,wangmiao1981/spark,xuanyuanking/spark,gengliangwang/spark,chuckchen/spark,gengliangwang/spark,ueshin/apache-spark,wangyum/spark,wangmiao1981/spark,vinodkc/spark,srowen/spark,xuanyuanking/spark,srowen/spark,holdenk/spark,wangyum/spark,taroplus/spark,wangyum/spark,ueshin/apache-spark,BryanCutler/spark,jiangxb1987/spark,wangyum/spark,cloud-fan/spark,chuckchen/spark,HyukjinKwon/spark,zzcclp/spark,shaneknapp/spark,gengliangwang/spark,maropu/spark,zzcclp/spark,srowen/spark,BryanCutler/spark,cloud-fan/spark,srowen/spark,shaneknapp/spark,jiangxb1987/spark,milliman/spark,HyukjinKwon/spark,zzcclp/spark,cloud-fan/spark,mahak/spark,cloud-fan/spark,rednaxelafx/apache-spark,rednaxelafx/apache-spark,rednaxelafx/apache-spark,maropu/spark,holdenk/spark,witgo/spark,rednaxelafx/apache-spark,BryanCutler/spark,hvanhovell/spark,wangmiao1981/spark,cloud-fan/spark,maropu/spark,srowen/spark,apache/spark,mahak/spark,zero323/spark,chuckchen/spark,gengliangwang/spark,jiangxb1987/spark,xuanyuanking/spark,rednaxelafx/apache-spark,holdenk/spark,xuanyuanking/spark,hvanhovell/spark,chuckchen/spark,taroplus/spark,wangmiao1981/spark,chuckchen/spark,HyukjinKwon/spark,gengliangwang/spark,zero323/spark,vinodkc/spark,gengliangwang/spark,dongjoon-hyun/spark,BryanCutler/spark,maropu/spark,HyukjinKwon/spark,JoshRosen/spark,JoshRosen/spark,holdenk/spark,nchammas/spark,ueshin/apache-spark,dongjoon-hyun/spark,dongjoon-hyun/spark,milliman/spark,apache/spark,srowen/spark,WeichenXu123/spark,ueshin/apache-spark,maropu/spark,jiangxb1987/spark,mahak/spark,shaneknapp/spark,mahak/spark,JoshRosen/spark,hvanhovell/spark,holdenk/spark,witgo/spark,vinodkc/spark,nchammas/spark,wangyum/spark,milliman/spark,HyukjinKwon/spark,taroplus/spark,mahak/spark,gengliangwang/spark,vinodkc/spark,zero323/spark,zero323/spark,zero323/spark,rednaxelafx/apache-spark,taroplus/spark,WeichenXu123/spark,zero323/spark,dongjoon-hyun/spark,dongjoon-hyun/spark,hvanhovell/spark,HyukjinKwon/spark,shaneknapp/spark