Update the openapi-maven-plugin, put version back to 1.0

Putting version back to 1.0 with the groupId change. I
think that is ok.

Author: rbygrave

openapi-maven-plugin/README.md

@@ -1,2 +1,21 @@
 # openapi-maven-plugin
 Maven plugin for OpenAPI generation (swagger)
+
+```xml
+
+<plugin>
+  <groupId>io.avaje</groupId>
+  <artifactId>openapi-maven-plugin</artifactId>
+  <version>1.0</version>
+  <executions>
+    <execution>
+      <id>main</id>
+      <phase>process-classes</phase>
+      <goals>
+        <goal>openapi</goal>
+      </goals>
+    </execution>
+  </executions>
+</plugin>
+
+```

openapi-maven-plugin/pom.xml

@@ -8,7 +8,7 @@
   </parent>
 
   <artifactId>openapi-maven-plugin</artifactId>
-  <version>1.4-SNAPSHOT</version>
+  <version>1.0</version>
   <packaging>maven-plugin</packaging>
   <name>openapi-maven-plugin</name>
   <url>https://avaje.io/http</url>