Update docs links to point to minor version branches

Closes gh-9986

docs/guides/spring-security-docs-guides.gradle

@@ -5,8 +5,7 @@ asciidoctor {
 	baseDir = file('src/docs/asciidoc')
 	options eruby: 'erubis'
 
-	def ghTag = snapshotBuild ? 'main' : project.version
-	def ghSamplesUrl = "https://github.com/spring-projects/spring-security-samples/tree/$ghTag"
+	def ghSamplesUrl = "https://github.com/spring-projects/spring-security-samples/tree/$samplesBranch"
 	attributes copycss : '',
 			icons : 'font',
 			'source-highlighter': 'prettify',

docs/manual/spring-security-docs-manual.gradle

@@ -18,7 +18,7 @@ asciidoctorj {
 	def ghTag = snapshotBuild ? 'main' : project.version
 	def ghUrl = "https://github.com/spring-projects/spring-security/tree/$ghTag"
 	def ghOldSamplesUrl = "https://github.com/spring-projects/spring-security/tree/5.4.x/samples"
-	def ghSamplesUrl = "https://github.com/spring-projects/spring-security-samples/tree/$ghTag"
+	def ghSamplesUrl = "https://github.com/spring-projects/spring-security-samples/tree/$samplesBranch"
 	def securityDocsUrl = "https://docs.spring.io/spring-security/site/docs/$docsTag"
 	def oldSecurityApiUrl = "https://docs.spring.io/spring-security/site/docs/5.4.x/api/"
 	def springVersion = "5.3.x"