Update scheduler.Dockerfile to go 1.18 to match admin (flyteorg#391)

Signed-off-by: Haytham Abuelfutuh <[email protected]>

Author: EngHabu

.github/workflows/checks.yml

@@ -80,7 +80,7 @@ jobs:
       version: ${{ needs.bump_version.outputs.version }}
       push: true
       repository: flyteorg/flytescheduler
-      dockerfile: Dockerfile.scheduler
+      dockerfile: scheduler.Dockerfile
     secrets:
       FLYTE_BOT_PAT: ${{ secrets.FLYTE_BOT_PAT }}
       FLYTE_BOT_USERNAME: ${{ secrets.FLYTE_BOT_USERNAME }}

Dockerfile.scheduler scheduler.Dockerfile

@@ -3,7 +3,7 @@
 # 
 # TO OPT OUT OF UPDATES, SEE https://github.com/lyft/boilerplate/blob/master/Readme.rst
 
-FROM golang:1.16.0-alpine3.13 as builder
+FROM golang:1.18-alpine3.15 as builder
 RUN apk add git openssh-client make curl
 
 # COPY only the go mod files for efficient caching
@@ -24,7 +24,7 @@ RUN make linux_compile_scheduler
 ENV PATH="/artifacts:${PATH}"
 
 # This will eventually move to centurylink/ca-certs:latest for minimum possible image size
-FROM alpine:3.13
+FROM alpine:3.15
 LABEL org.opencontainers.image.source https://github.com/flyteorg/flyteadmin
 
 COPY --from=builder /artifacts /bin