Fix JdkObsolete Error Prone errors by using Charset overloads

The newer Error Prone pulled in with the Gerrit rules_java 9.8.0 bump
reports JdkObsolete for URLEncoder.encode(String, String). Switch to
the Charset overload and drop the now-dead UnsupportedEncodingException
try/catch blocks and imports.

Change-Id: Ib32a58f36e85b1692bd555653f5a9cf991a5d367

src/main/java/com/googlesource/gerrit/plugins/download/scheme/HttpScheme.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/download/scheme/HttpScheme.java b/src/main/java/com/googlesource/gerrit/plugins/download/scheme/HttpScheme.java
index 8ef7957..c87b8e3 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/download/scheme/HttpScheme.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/download/scheme/HttpScheme.java
@@ -30,7 +30,6 @@
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
-import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
@@ -84,11 +83,7 @@
       getHttpUserName()
           .ifPresent(
               u -> {
-                try {
-                  r.append(URLEncoder.encode(u, StandardCharsets.UTF_8.name()));
-                } catch (UnsupportedEncodingException e) {
-                  throw new IllegalStateException("No UTF-8 support", e);
-                }
+                r.append(URLEncoder.encode(u, StandardCharsets.UTF_8));
                 r.append("@");
               });
       r.append(host);

src/main/java/com/googlesource/gerrit/plugins/download/scheme/SshScheme.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/download/scheme/SshScheme.java b/src/main/java/com/googlesource/gerrit/plugins/download/scheme/SshScheme.java
index 9149a13..8349091 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/download/scheme/SshScheme.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/download/scheme/SshScheme.java
@@ -28,7 +28,6 @@
 import com.google.gerrit.server.ssh.SshAdvertisedAddresses;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
-import java.io.UnsupportedEncodingException;
 import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URLEncoder;
@@ -132,11 +131,7 @@
     r.append("ssh://");
 
     if (includeUserName) {
-      try {
-        r.append(URLEncoder.encode(username.get(), StandardCharsets.UTF_8.name()));
-      } catch (UnsupportedEncodingException e) {
-        throw new IllegalStateException("No UTF-8 support", e);
-      }
+      r.append(URLEncoder.encode(username.get(), StandardCharsets.UTF_8));
       r.append("@");
     }
 

src/test/java/com/googlesource/gerrit/plugins/download/DownloadCommandTest.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/download/DownloadCommandTest.java b/src/test/java/com/googlesource/gerrit/plugins/download/DownloadCommandTest.java
index 11bd210..ba216a4 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/download/DownloadCommandTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/download/DownloadCommandTest.java
@@ -28,7 +28,6 @@
 import com.google.inject.util.Providers;
 import com.googlesource.gerrit.plugins.download.scheme.HttpScheme;
 import com.googlesource.gerrit.plugins.download.scheme.SshScheme;
-import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.Optional;
@@ -90,8 +89,8 @@
     public final int sshPort = 29418;
     public final int sshdAdvertisedPrimaryAddress = 39418;
 
-    public String urlEncodedUserName() throws UnsupportedEncodingException {
-      return URLEncoder.encode(userName, StandardCharsets.UTF_8.name());
+    public String urlEncodedUserName() {
+      return URLEncoder.encode(userName, StandardCharsets.UTF_8);
     }
 
     public String canonicalUrl() {