Fix/suppress aapt/aapt2 google-explicit-constructor warnings

* Add explicit to conversion constructors/operators
* Use NOLINT or NOLINTNEXTLINE to suppress warnings on intended converters

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: Ie02101ea7c422e8add535c111a30a2f21ead0ace
diff --git a/tools/aapt2/java/ProguardRules.h b/tools/aapt2/java/ProguardRules.h
index 46827ee..c53f307 100644
--- a/tools/aapt2/java/ProguardRules.h
+++ b/tools/aapt2/java/ProguardRules.h
@@ -44,7 +44,7 @@
  public:
   KeepSet() = default;
 
-  KeepSet(bool conditional_keep_rules) : conditional_keep_rules_(conditional_keep_rules) {
+  explicit KeepSet(bool conditional_keep_rules) : conditional_keep_rules_(conditional_keep_rules) {
   }
 
   inline void AddManifestClass(const UsageLocation& file, const std::string& class_name) {