Change doma-processor to compile scoped with optional

Author: backpaper0

README.md

@@ -71,7 +71,7 @@ Add the following dependencies to `pom.xml` so that we can use Doma with Spring
     <groupId>org.seasar.doma</groupId>
     <artifactId>doma-processor</artifactId>
     <version>2.30.0</version>
-    <scope>provided</scope>
+    <optional>true</optional>
 </dependency>
 ```
 

doma-spring-boot-samples/doma-spring-boot-sample-entity-listener/pom.xml

@@ -27,7 +27,7 @@
             <groupId>org.seasar.doma</groupId>
             <artifactId>doma-processor</artifactId>
             <version>${doma.version}</version>
-            <scope>provided</scope>
+            <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>org.seasar.doma.boot</groupId>

doma-spring-boot-samples/doma-spring-boot-sample-event-handler/pom.xml

@@ -27,7 +27,7 @@
             <groupId>org.seasar.doma</groupId>
             <artifactId>doma-processor</artifactId>
             <version>${doma.version}</version>
-            <scope>provided</scope>
+            <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>org.seasar.doma.boot</groupId>

doma-spring-boot-samples/doma-spring-boot-sample-simple/pom.xml

@@ -27,7 +27,7 @@
             <groupId>org.seasar.doma</groupId>
             <artifactId>doma-processor</artifactId>
             <version>${doma.version}</version>
-            <scope>provided</scope>
+            <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>org.seasar.doma.boot</groupId>

doma-spring-boot-samples/doma-spring-boot-sample-two-datasource/pom.xml

@@ -27,7 +27,6 @@
 			<groupId>org.seasar.doma</groupId>
 			<artifactId>doma-processor</artifactId>
 			<version>${doma.version}</version>
-			<scope>compile</scope>
 			<optional>true</optional>
 		</dependency>
 		<dependency>