Add Apple Silicon support

[aldnav]

When building on MacBook Air (M1, 2020) I get the following

➜  endpoints git:(master) docker-compose up
Creating network "endpoints_default" with the default driver
Creating volume "endpoints_pgdata" with default driver
Pulling postgres (postgres:10.2-alpine)...
10.2-alpine: Pulling from library/postgres
b78042c299ad: Pull complete
6fd45b97b6c2: Pull complete
1b32a887a236: Pull complete
ee1f330d8736: Pull complete
08af2de580ac: Pull complete
d9996e061e4b: Pull complete
f03b674831a0: Pull complete
1297a4ee831c: Pull complete
994cfba0fef5: Pull complete
ec6f68f4ad22: Pull complete
Digest: sha256:2cdf8430d7c1f59b3d3808f672944491aabf0fdf15da5b5e158e9fa4162453bf
Status: Downloaded newer image for postgres:10.2-alpine
Pulling redis (redis:alpine)...
alpine: Pulling from library/redis
b3c136eddcbf: Pull complete
f9cb7a578000: Pull complete
9052ca636db2: Pull complete
e5d89d1877d1: Pull complete
3ff42958ee37: Pull complete
dc727f51c434: Pull complete
Digest: sha256:5916c280afae05baf0dc9a0cc82fa8e51477bdbfc72f60a5c14fd2b7735bcf07
Status: Downloaded newer image for redis:alpine
Building endpoint-service
[+] Building 3.3s (3/3) FINISHED
 => [internal] load build definition from Dockerfile                                                                                                                                                                                                                       0.0s
 => => transferring dockerfile: 494B                                                                                                                                                                                                                                       0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                          0.0s
 => => transferring context: 2B                                                                                                                                                                                                                                            0.0s
 => ERROR [internal] load metadata for docker.io/library/python:3.6-jessie                                                                                                                                                                                                 3.3s
------
 > [internal] load metadata for docker.io/library/python:3.6-jessie:
------
failed to solve with frontend dockerfile.v0: failed to create LLB definition: no match for platform in manifest sha256:1e428d8e87bcc9cd156539c5afeb60075a518b20d2d4657db962df90e6552fa5: not found
ERROR: Service 'endpoint-service' failed to build : Build failed