fix(dep-check): remove react-native-linear-gradient from banned libraries (#1875)

At the time of this commit, React Native Linear Gradient has been
updated 2 months ago (2022/07/04), thus invalidating the "unmaintained"
adjective. Not sure about the actual performance implications so I might
also simply update the message to something less alarming.

See also
https://github.com/react-native-linear-gradient/react-native-linear-gradient/issues/570

.changeset/afraid-bulldogs-stare.md

@@ -0,0 +1,5 @@
+---
+"@rnx-kit/dep-check": minor
+---
+
+Do not warn for recent react-native-linear-gradient versions

packages/dep-check/src/presets/banned.ts

@@ -15,9 +15,9 @@ const bannedPackages: ExcludedPackage[] = [
   },
   {
     name: "react-native-linear-gradient",
-    version: "*",
+    version: "<2.6.0",
     reason:
-      "This package is unmaintained and causes significant degradation in app start up time.",
+      "This package causes significant degradation in app start up time prior to 2.6.0.",
   },
   {
     name: "react-native-lazy-index",

packages/dep-check/test/__snapshots__/check.test.ts.snap

@@ -21,7 +21,7 @@ Array [
   Array [
     "warn",
     "Known bad packages are found in '@rnx-kit/dep-check':
-    react-native-linear-gradient@*: This package is unmaintained and causes significant degradation in app start up time.",
+    react-native-linear-gradient@<2.6.0: This package causes significant degradation in app start up time prior to 2.6.0.",
   ],
 ]
 `;
@@ -31,7 +31,7 @@ Array [
   Array [
     "warn",
     "Known bad packages are found in '@rnx-kit/dep-check':
-    react-native-linear-gradient@*: This package is unmaintained and causes significant degradation in app start up time.",
+    react-native-linear-gradient@<2.6.0: This package causes significant degradation in app start up time prior to 2.6.0.",
   ],
 ]
 `;