Add support for the new --exclude flag for ADD and COPY instructions

[rcjsuen]

# syntax=docker/dockerfile-upstream:master-labs
FROM alpine
ADD --exclude=*.x --exclude=*.y . .
COPY --exclude=*.txt --exclude=*.md . .

$ docker build .
[+] Building 0.8s (10/10) FINISHED                                                                                                   docker:default
 => [internal] load build definition from Dockerfile                                                                                           0.0s
 => => transferring dockerfile: 175B                                                                                                           0.0s
 => [internal] load .dockerignore                                                                                                              0.0s
 => => transferring context: 2B                                                                                                                0.0s
 => resolve image config for docker.io/docker/dockerfile-upstream:master-labs                                                                  0.1s
 => CACHED docker-image://docker.io/docker/dockerfile-upstream:master-labs@sha256:a671bfcbd99e8f368e8177e7f3c63159793fe9e64b87a7dd9771185d3cd  0.0s
 => [internal] load metadata for docker.io/library/alpine:latest                                                                               0.1s
 => CACHED [1/3] FROM docker.io/library/alpine:latest@sha256:c5b1261d6d3e43071626931fc004f70149baeba2c8ec672bd4f27761f8e1ad6b                  0.0s
 => [internal] load build context                                                                                                              0.0s
 => => transferring context: 4.62kB                                                                                                            0.0s
 => [2/3] ADD --exclude=*.x --exclude=*.y . .                                                                                                  0.1s
 => [3/3] COPY --exclude=*.txt --exclude=*.md . .                                                                                              0.1s
 => exporting to image                                                                                                                         0.0s
 => => exporting layers                                                                                                                        0.0s
 => => writing image sha256:5dcd6e7288160ef7499e9ccb8d4b01aeb1d11706c5f01813dd58aee8bf38df4b     

[rcjsuen]

Closed by 69280a6.