Bump bouncycastleVersion from 1.80 to 1.81

Bumps `bouncycastleVersion` from 1.80 to 1.81.

Updates `org.bouncycastle:bcprov-jdk18on` from 1.80 to 1.81
- [Changelog](https://github.com/bcgit/bc-java/blob/main/docs/releasenotes.html)
- [Commits](https://github.com/bcgit/bc-java/commits)

Updates `org.bouncycastle:bcpkix-jdk18on` from 1.80 to 1.81
- [Changelog](https://github.com/bcgit/bc-java/blob/main/docs/releasenotes.html)
- [Commits](https://github.com/bcgit/bc-java/commits)

---
updated-dependencies:
- dependency-name: org.bouncycastle:bcprov-jdk18on
  dependency-version: '1.81'
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.bouncycastle:bcpkix-jdk18on
  dependency-version: '1.81'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -23,7 +23,7 @@ ext {
     pdfboxVersion = "3.0.5"
     imageioVersion = "3.12.0"
     lombokVersion = "1.18.38"
-    bouncycastleVersion = "1.80"
+    bouncycastleVersion = "1.81"
     springSecuritySamlVersion = "6.5.0"
     openSamlVersion = "4.3.2"
     commonmarkVersion = "0.24.0"

proprietary/build.gradle

@@ -19,7 +19,7 @@ dependencies {
     implementation 'com.bucket4j:bucket4j_jdk17-core:8.14.0'
 
     // https://mvnrepository.com/artifact/com.bucket4j/bucket4j_jdk17
-    implementation 'org.bouncycastle:bcprov-jdk18on:1.80'
+    implementation 'org.bouncycastle:bcprov-jdk18on:1.81'
 
     implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity5:3.1.3.RELEASE'
     api 'io.micrometer:micrometer-registry-prometheus'