enable lint PackageManagerGetSignatures as error

app/lint.xml

@@ -24,6 +24,7 @@
     <issue id="StringFormatCount" severity="error"/>
     <issue id="UnsafeProtectedBroadcastReceiver" severity="error"/>
     <issue id="GetInstance" severity="error"/>
+    <issue id="PackageManagerGetSignatures" severity="error"/>
 
     <issue id="PluralsCandidate" severity="error"/>
     <issue id="HardcodedText" severity="error"/>

app/src/main/java/org/fdroid/fdroid/data/InstalledAppProviderService.java

@@ -273,7 +273,13 @@ public class InstalledAppProviderService extends JobIntentService {
      * <p>
      * Can still return null, as there is potentially race conditions to do with uninstalling apps
      * such that querying the {@link PackageManager} for a given package may throw an exception.
+     * <p>
+     * The {@code PackageManagerGetSignatures} lint check is not relevant here since this is doing
+     * nothing related to verifying the signature.  The APK signatures are just processed to
+     * produce the unique ID of the signer to determine compatibility.  This {@code Service} does
+     * nothing related to checking valid APK signatures.
      */
+    @SuppressWarnings("PackageManagerGetSignatures")
     @Nullable
     private PackageInfo getPackageInfo(Intent intent, String packageName) {
         PackageInfo packageInfo = intent.getParcelableExtra(EXTRA_PACKAGE_INFO);