fix: update min IDEA version to 2024.1.7 and fix IconLoader compatibility

- Update minimum supported IDEA version from 2021.2.1 to 2024.1.7
- Remove support for outdated IDEA versions (2021.2.1, 2022.2.3)
- Fix binary incompatibility with IconLoader.findIcon(URL) method
- Replace IconLoader.findIcon(URL) with javax.swing.ImageIcon for compatibility
- This resolves NoSuchMethodError at runtime in IDEA 2024.1+

Author: tangcent

idea-plugin/build.gradle.kts

@@ -7,9 +7,9 @@ version = properties["plugin_version"]!!
 
 val intellijVersions = arrayOf(
     mapOf("jdk" to 21, "version" to "2025.1.2", "since" to "251"),
-    mapOf("jdk" to 17, "version" to "2023.1.3", "since" to "231"),
-    mapOf("jdk" to 15, "version" to "2022.2.3", "since" to "222"),
-    mapOf("jdk" to 11, "version" to "2021.2.1", "since" to "212")
+    mapOf("jdk" to 17, "version" to "2024.1.7", "since" to "241"),
+    mapOf("jdk" to 15, "version" to "2024.1.7", "since" to "241"),
+    mapOf("jdk" to 11, "version" to "2024.1.7", "since" to "241")
 )
 
 val javaVersion = JavaVersion.current().majorVersion.toInt()

idea-plugin/src/main/kotlin/com/itangcent/idea/icons/EasyIcons.kt

@@ -183,7 +183,8 @@ object DefaultIconLoader : IconLoader {
 
     override fun findIcon(url: URL?): Icon? {
         url ?: return null
-        return com.intellij.openapi.util.IconLoader.findIcon(tryLoadCache(url))
+        val cachedUrl = tryLoadCache(url)
+        return javax.swing.ImageIcon(cachedUrl)
     }
 
     private fun tryLoadCache(url: URL): URL {