Add new go:build lines for go 1.17

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

prometheus/collectors/dbstats_collector_go115.go

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build go1.15
 // +build go1.15
 
 package collectors

prometheus/collectors/dbstats_collector_pre_go115.go

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !go1.15
 // +build !go1.15
 
 package collectors

prometheus/process_collector_other.go

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows
 // +build !windows
 
 package prometheus

prometheus/process_collector_test.go

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build linux
 // +build linux
 
 package prometheus