Update Spire version and make Dockerfile support multi-arch build (#604)

* Update Spire version and make Dockerfile support multi-arch build

Signed-off-by: Nikita Skrynnik <nikita.skrynnik@xored.com>

* Use a default value for BUILDARCH agrument

Signed-off-by: Nikita Skrynnik <nikita.skrynnik@xored.com>

---------

Signed-off-by: Nikita Skrynnik <nikita.skrynnik@xored.com>

Dockerfile

@@ -5,10 +5,11 @@ ENV PATH ${PATH}:/go/bin
 ENV GO111MODULE=on
 ENV CGO_ENABLED=0
 ENV GOBIN=/bin
+ARG BUILDARCH=amd64
 RUN rm -r /etc/vpp
 RUN go install github.com/go-delve/delve/cmd/dlv@v1.21.0
-ADD https://github.com/spiffe/spire/releases/download/v1.2.2/spire-1.2.2-linux-x86_64-glibc.tar.gz .
-RUN tar xzvf spire-1.2.2-linux-x86_64-glibc.tar.gz -C /bin --strip=2 spire-1.2.2/bin/spire-server spire-1.2.2/bin/spire-agent
+ADD https://github.com/spiffe/spire/releases/download/v1.8.0/spire-1.8.0-linux-${BUILDARCH}-musl.tar.gz .
+RUN tar xzvf spire-1.8.0-linux-${BUILDARCH}-musl.tar.gz -C /bin --strip=2 spire-1.8.0/bin/spire-server spire-1.8.0/bin/spire-agent
 
 FROM go as build
 WORKDIR /build