Fixes: -buildmode=pie requires external (cgo) linking, but cgo is not enabled

This is enforced on riscv64 since go 1.22
--- a/Makefile
+++ b/Makefile
@@ -40,7 +40,7 @@
 build: validate-go-version clean $(BINARY)
 
 $(BINARY):
-	CGO_ENABLED=0 $(GO) build -a -installsuffix cgo -ldflags="-X github.com/oauth2-proxy/oauth2-proxy/v7/pkg/version.VERSION=${VERSION}" -o $@ github.com/oauth2-proxy/oauth2-proxy/v7
+	$(GO) build -a -installsuffix cgo -ldflags="-X github.com/oauth2-proxy/oauth2-proxy/v7/pkg/version.VERSION=${VERSION}" -o $@ github.com/oauth2-proxy/oauth2-proxy/v7
 
 DOCKER_BUILD_PLATFORM         ?= linux/amd64,linux/arm64,linux/ppc64le,linux/arm/v7,linux/s390x
 DOCKER_BUILD_RUNTIME_IMAGE    ?= gcr.io/distroless/static:nonroot