ci: add a validate-tests bake target

Dockerfile

@@ -47,3 +47,10 @@ RUN --mount=target=/context \
     exit 1
   fi
 EOT
+
+FROM base AS test
+RUN apk add --no-cache gcc musl-dev
+WORKDIR /src
+RUN --mount=target=. \
+  --mount=target=/root/.cache,type=cache \
+  CGO_ENABLED=1 go test -race -v ./...

docker-bake.hcl

@@ -17,7 +17,10 @@ group "default" {
 }
 
 group "validate" {
-  targets = ["validate-docs"]
+  targets = [
+    "validate-docs",
+    "validate-tests"
+  ]
 }
 
 target "validate-docs" {
@@ -37,3 +40,9 @@ target "update-docs" {
   target = "docs-update"
   output = ["./docs/reference"]
 }
+
+target "validate-tests" {
+  inherits = ["_common"]
+  target = "test"
+  output = ["type=cacheonly"]
+}