Replace JSR-305 annotations with spotbugs annotations (#49)

Annotations for Nonnull, CheckForNull, and several others were proposed
for Java as part of dormant Java specification request JSR-305. The
proposal never became a part of standard Java.

Jenkins plugins should switch from using JSR-305 annotations to use
Spotbugs annotations that provide the same semantics.

The [mailing list discussion](https://groups.google.com/g/jenkinsci-dev/c/uE1wwtVi1W0/m/gLxdEJmlBQAJ)
from James Nord describes the affected annotations and why they should
be replaced with annotations that are actively maintained.

The ["Improve a plugin" tutorial](https://www.jenkins.io/doc/developer/tutorial-improve/replace-jsr-305-annotations/)
provides instructions to perform this change.

An [OpenRewrite recipe](https://docs.openrewrite.org/recipes/jenkins/javaxannotationstospotbugs)
is also available and is even better than the tutorial.

Confirmed that automated tests pass on Linux with Java 21.

Author: MarkEWaite

src/main/java/hudson/plugins/deploy/ContainerAdapterDescriptor.java

@@ -3,7 +3,7 @@
 import java.io.IOException;
 import java.net.URL;
 
-import javax.annotation.CheckForNull;
+import edu.umd.cs.findbugs.annotations.CheckForNull;
 
 import org.apache.commons.lang.StringUtils;
 import org.kohsuke.accmod.Restricted;

src/main/java/hudson/plugins/deploy/DeployPublisher.java

@@ -9,7 +9,7 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import javax.annotation.Nonnull;
+import edu.umd.cs.findbugs.annotations.NonNull;
 
 import org.jenkinsci.Symbol;
 import org.kohsuke.accmod.Restricted;
@@ -86,7 +86,7 @@ public void setContextPath (String contextPath) {
     }
 
     @Override
-    public void perform(@Nonnull Run<?, ?> run, @Nonnull FilePath workspace, @Nonnull Launcher launcher, @Nonnull TaskListener listener) throws InterruptedException, IOException {
+    public void perform(@NonNull Run<?, ?> run, @NonNull FilePath workspace, @NonNull Launcher launcher, @NonNull TaskListener listener) throws InterruptedException, IOException {
         Result result = run.getResult();
         if (onFailure || result == null || Result.SUCCESS.equals(result)) {
             if (!workspace.exists()) {

src/main/java/hudson/plugins/deploy/PasswordProtectedAdapterCargo.java

@@ -19,7 +19,7 @@
 import org.kohsuke.accmod.restrictions.DoNotUse;
 import org.kohsuke.accmod.restrictions.NoExternalUse;
 
-import javax.annotation.CheckForNull;
+import edu.umd.cs.findbugs.annotations.CheckForNull;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;