chore(release): bump Maven 7.21.1, PyPI 0.21.1, NuGet 0.21.1

Version bumps for the coordinated 0.21.1 PATCH. npm is bumped separately by
scripts/release.mjs, which owns its own commit/tag/publish sequence.

Bumped ahead of the npm script deliberately: that script tags v0.21.1 and pushes,
and the tag-triggered Java release-gate resolves poms at the tagged commit -- so
the poms must already be at 7.21.1 when the tag lands.

Used the tree-wide grep+sed per RELEASING.md rather than `mvn versions:set`,
which only walks the reactor and would silently leave the two reactor-EXCLUDED
integration-test modules behind. scripts/check-pom-versions.sh confirms all 17
poms including both excluded modules are in sync.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015TqsuDye2SfXGf43vuoD3n

Author: dmealing

server/csharp/Directory.Build.props

@@ -8,7 +8,7 @@
   -->
 
   <PropertyGroup>
-    <Version>0.21.0</Version>
+    <Version>0.21.1</Version>
     <Authors>Doug Mealing</Authors>
     <Company>Doug Mealing LLC</Company>
     <Product>MetaObjects</Product>

server/java/codegen-base/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>com.metaobjects</groupId>
         <artifactId>metaobjects</artifactId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <artifactId>metaobjects-codegen-base</artifactId>

server/java/codegen-kotlin/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>com.metaobjects</groupId>
     <artifactId>metaobjects</artifactId>
-    <version>7.21.0</version>
+    <version>7.21.1</version>
   </parent>
 
   <artifactId>metaobjects-codegen-kotlin</artifactId>

server/java/codegen-mustache/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>com.metaobjects</groupId>
         <artifactId>metaobjects</artifactId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <artifactId>metaobjects-codegen-mustache</artifactId>

server/java/codegen-plantuml/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>com.metaobjects</groupId>
         <artifactId>metaobjects</artifactId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <artifactId>metaobjects-codegen-plantuml</artifactId>

server/java/codegen-spring/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>com.metaobjects</groupId>
         <artifactId>metaobjects</artifactId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <artifactId>metaobjects-codegen-spring</artifactId>

server/java/core-spring/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>com.metaobjects</groupId>
         <artifactId>metaobjects</artifactId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <artifactId>metaobjects-core-spring</artifactId>

server/java/integration-tests-kotlin/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>com.metaobjects</groupId>
     <artifactId>metaobjects</artifactId>
-    <version>7.21.0</version>
+    <version>7.21.1</version>
   </parent>
 
   <artifactId>metaobjects-integration-tests-kotlin</artifactId>

server/java/integration-tests/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>com.metaobjects</groupId>
     <artifactId>metaobjects</artifactId>
-    <version>7.21.0</version>
+    <version>7.21.1</version>
   </parent>
 
   <artifactId>metaobjects-integration-tests</artifactId>

server/java/maven-plugin/pom.xml

@@ -2,7 +2,7 @@
     <parent>
         <artifactId>metaobjects</artifactId>
         <groupId>com.metaobjects</groupId>
-        <version>7.21.0</version>
+        <version>7.21.1</version>
     </parent>
 
     <modelVersion>4.0.0</modelVersion>