How do I fix the Go module error in an updated ClamAV Docker container build?

I'm trying to revive the ClamAV Docker container by updating its base image from malice/alpine to alpine:latest (using lines from the original malice/alpine Dockerfile). This update to Alpine works, but when I changed go get to go install (in response to deprecation warnings), I now encounter the error:

go: go.mod file not found in current directory or any parent directory; see 'go help modules'.

I need guidance on resolving this error so that the old version installs and runs successfully. Below is my current Dockerfile for reference:

DOCKERFILECopied
FROM alpine:latest

LABEL maintainer "https://github.com/blacktop"

LABEL malice.plugin.repository = "https://github.com/malice-plugins/clamav.git"
LABEL malice.plugin.category="av"
LABEL malice.plugin.mime="*"
LABEL malice.plugin.docker.engine="*"

COPY . /go/src/github.com/malice-plugins/clamav
RUN apk add --no-cache tini su-exec
RUN set -x 
  && echo "===> Add malice user and malware folder..." 
  && addgroup malice 
  && adduser -S -G malice malice 
  && mkdir /malware 
  && chown -R malice:malice /malware
RUN apk --update add --no-cache clamav ca-certificates
RUN apk --update add --no-cache -t .build-deps 
  build-base 
  mercurial 
  musl-dev 
  openssl 
  bash 
  wget 
  git 
  gcc 
  go 
  && echo "Building avscan Go binary..." 
  && cd /go/src/github.com/malice-plugins/clamav 
  && export GOPATH=/go 
  && go version 
  && go install \ # This line was changed by me from 'go get'
  && go build -ldflags "-s -w -X main.Version=v$(cat VERSION) -X main.BuildTime=$(date -u +%Y%m%d)" -o /bin/avscan 
  && rm -rf /go /usr/local/go /usr/lib/go /tmp/* 
  && apk del --purge .build-deps

# Update ClamAV Definitions
RUN mkdir -p /opt/malice 
  && chown malice /opt/malice 
  && freshclam

# Add EICAR Test Virus File to malware folder
#ADD http://www.eicar.org/download/eicar.com.txt /malware/EICAR

RUN chown malice -R /malware

WORKDIR /malware

ENTRYPOINT ["/bin/avscan"]
CMD ["--help"]