Fix whitespace in default Make variables

[ciarams87]

Proposed changes

There is whitespace at the end of some of the default Make variables including TARGET ?= local because it is including the whitespace between the var and the comment on the same line. This means that make build is not doing anything without explicitly passing in the TARGET, e.g.make build TARGET=local. This commit removes the whitespace and returns the previous behaviour.

Current behaviour:

~/workspace/github/nginxinc/kubernetes-ingress master > make build
Docker version 20.10.10, build b485636

New behaviour:

~/workspace/github/nginxinc/kubernetes-ingress chore/fix-makefile-whitespace > make build
Docker version 20.10.10, build b485636
go version go1.17.1 darwin/amd64
CGO_ENABLED=0 GO111MODULE=on GOOS=linux go build -trimpath -ldflags "-s -w -X main.version=v2.0.3-SNAPSHOT-b90d4e7 -X main.commit=b90d4e733e1a799b2e16105ad07a6e9ee9a3e989 -X main.date=2021-12-06T12:29:23Z" -o nginx-ingress github.com/nginxinc/kubernetes-ingress/cmd/nginx-ingress

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have rebased my branch onto master
• I will ensure my PR is targeting the master branch and pulling from my branch from my own fork