Upgrade to Biweekly 0.6.8

Author: wilkinsona

build.gradle

@@ -22,7 +22,7 @@ dependencies {
 	checkstyle("io.spring.javaformat:spring-javaformat-checkstyle:$javaFormatVersion")
 
 	implementation(platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES))
-	implementation('net.sf.biweekly:biweekly:0.6.7')
+	implementation('net.sf.biweekly:biweekly:0.6.8')
 	implementation('org.apache.httpcomponents.client5:httpclient5')
 	implementation('org.springframework.boot:spring-boot-starter-web')
 	implementation('org.webjars:fullcalendar:5.11.3')