fix: enable cgo when pure tag is passed

This enables running tests that require CGO like `go test -race` when
using pure-go sqlite through passing `-tags pure` build flag

Author: aymanbagabas

sqlite_cgo.go

@@ -1,5 +1,5 @@
-//go:build cgo
-// +build cgo
+//go:build cgo && !pure
+// +build cgo,!pure
 
 package sqlite
 

sqlite_cgo_test.go

@@ -1,5 +1,5 @@
-//go:build cgo
-// +build cgo
+//go:build cgo && !pure
+// +build cgo,!pure
 
 package sqlite
 

sqlite_pure.go

@@ -1,5 +1,5 @@
-//go:build !cgo
-// +build !cgo
+//go:build !cgo || (cgo && pure)
+// +build !cgo cgo,pure
 
 package sqlite
 

sqlite_pure_test.go

@@ -1,5 +1,5 @@
-//go:build !cgo
-// +build !cgo
+//go:build !cgo || (cgo && pure)
+// +build !cgo cgo,pure
 
 package sqlite