Compile the source code according to the Build.md document

[PengTaoWW]

Environmental Info:
K3s Version: master v1.19.2-rc2+k3s1 release-1.25

Node(s) CPU architecture, OS, and Version: cpu amd64 ; os: Linux, kernel : 5.4.119-20.0009.20

Cluster Configuration: one node

Describe the bug: Compile the source code according to the Build.md document like ：
go: downloading golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
--> 01d0850b086
STEP 12/26: RUN rm -rf /go/src /go/pkg
--> 625a003015c
STEP 13/26: RUN if [ "$(go env GOARCH)" = "amd64" ]; then curl -sL https://raw.githubusercontent.com/golangci/golangci-lint/v1.45.2/install.sh | sh -s; fi
golangci/golangci-lint info checking GitHub for latest tag
golangci/golangci-lint info found version: 1.52.0 for v1.52.0/linux/amd64
golangci/golangci-lint info installed ./bin/golangci-lint
--> c2b4c3780be
STEP 14/26: ARG SELINUX=true
--> 490b2a8e6e5
STEP 15/26: ENV SELINUX $SELINUX
--> ba63c21fe26
STEP 16/26: ENV DAPPER_RUN_ARGS --privileged -v k3s-cache:/go/src/github.com/k3s-io/k3s/.cache -v trivy-cache:/root/.cache/trivy
--> 566af4c3b67
STEP 17/26: ENV DAPPER_ENV REPO TAG DRONE_TAG IMAGE_NAME SKIP_VALIDATE SKIP_AIRGAP AWS_SECRET_ACCESS_KEY AWS_ACCESS_KEY_ID GITHUB_TOKEN GOLANG DEBUG
--> 921a0ed033d
STEP 18/26: ENV DAPPER_SOURCE /go/src/github.com/k3s-io/k3s/
--> 369865d2c77
STEP 19/26: ENV DAPPER_OUTPUT ./bin ./dist ./build/out ./build/static ./pkg/static ./pkg/deploy
--> 2900dc09324
STEP 20/26: ENV DAPPER_DOCKER_SOCKET true
--> 6e52dc9092e
STEP 21/26: ENV HOME ${DAPPER_SOURCE}
--> a46f8572ff8
STEP 22/26: ENV CROSS true
--> 99c9f6f84ca
STEP 23/26: ENV STATIC_BUILD true
--> b750f814a17
STEP 24/26: WORKDIR ${DAPPER_SOURCE}
--> d6fb6106ba1
STEP 25/26: ENTRYPOINT ["./scripts/entry.sh"]
--> 707d5db38d4
STEP 26/26: CMD ["ci"]
COMMIT k3s:release-1-25
--> 1df43e7128b
Successfully tagged localhost/k3s:release-1-25
1df43e7128be4d1ab3738febfef44c3dfa18df558bc2ab36993111a3fd1a1466
FATA[0138] invalid character 'E' looking for beginning of value
make: *** [Makefile:11：download] error 1

Steps To Reproduce:

• Installed K3s:

Expected behavior:
run success

Actual behavior:

Additional context / logs: