Fix arch of apk packages

[Dean-Coakley]

Proposed changes

Fix architecture of arm apk packages

Bug

First noticed in pipeline runs:

Before

# Create apk packages
/bin/sh: 3: [: aarch64: unexpected operator
using apk packager...
created package: ./build/packages/apk/v3.13/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.14/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.15/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.16/aarch64/nginx-agent-2.19.0.apk
/bin/sh: 3: [: x86_64: unexpected operator
using apk packager...
created package: ./build/packages/apk/v3.13/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.14/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.15/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.16/x86_64/nginx-agent-2.19.0.apk

After

Ref: https://github.com/nginx/agent/actions/runs/3650619616/jobs/6166828489#step:7:64

# Create apk packages
using apk packager...
created package: ./build/packages/apk/v3.13/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.14/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.15/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.16/aarch64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.13/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.14/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.15/x86_64/nginx-agent-2.19.0.apk
using apk packager...
created package: ./build/packages/apk/v3.16/x86_64/nginx-agent-2.19.0.apk

Failing if condition resulted in amd64 binaries placed in arm package

Checklist

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

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md)