Update Examples action to run on Windows, MacOs, and Linux

[keastrid]

Summary

Demonstration of #973 and testing to make sure it won't occur again by running in CI

Release Note

NONE

Documentation

No documentation changes needed

[loosebazooka]

Okay, I think I found the issue, if you update this PR with

diff --git a/sigstore-java/src/main/java/dev/sigstore/encryption/certificates/Certificates.java b/sigstore-java/src/main/java/dev/sigstore/encryption/certificates/Certificates.java
index 9308efd..9cf75c7 100644
--- a/sigstore-java/src/main/java/dev/sigstore/encryption/certificates/Certificates.java
+++ b/sigstore-java/src/main/java/dev/sigstore/encryption/certificates/Certificates.java
@@ -48,7 +48,7 @@ public class Certificates {
       pemWriter.writeObject(cert);
       pemWriter.flush();
     }
-    return certWriter.toString();
+    return certWriter.toString().replaceAll("\r\n", "\n");
   }

   /** Convert a certificate to a PEM encoded certificate. */
@@ -94,7 +94,7 @@ public class Certificates {
       }
       pemWriter.flush();
     }
-    return certWriter.toString();
+    return certWriter.toString().replaceAll("\r\n", "\n");
   }

essentially stripping out the \r everywhere on PEM write, then we'll pass

[keastrid]

It seems to still fail, sadly https://github.com/keastrid/sigstore-java/actions/runs/15332645105/job/43142891162

[loosebazooka]

Yeah that's against the latest release. It's fine. If you comment out the release build for Windows you can see it pass on the dev build. But I would leave it in. We can probably think about publishing a fixed version soon

[loosebazooka]

thanks for this @keastrid