Bump slf4j-api from 1.7.25 to 1.7.26 in /examples

Bumps [slf4j-api](https://github.com/qos-ch/slf4j) from 1.7.25 to 1.7.26.
- [Release notes](https://github.com/qos-ch/slf4j/releases)
- [Commits](qos-ch/slf4j@v_1.7.25...v_1.7.26)

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

examples/linked-container/build.gradle

@@ -6,7 +6,7 @@ repositories {
     jcenter()
 }
 dependencies {
-    compileOnly 'org.slf4j:slf4j-api:1.7.25'
+    compileOnly 'org.slf4j:slf4j-api:1.7.26'
     implementation 'com.squareup.okhttp3:okhttp:3.12.1'
     implementation 'org.json:json:20180813'
     testImplementation 'org.postgresql:postgresql:42.2.5'

examples/redis-backed-cache-testng/build.gradle

@@ -7,7 +7,7 @@ repositories {
 }
 
 dependencies {
-    compileOnly 'org.slf4j:slf4j-api:1.7.25'
+    compileOnly 'org.slf4j:slf4j-api:1.7.26'
     implementation 'redis.clients:jedis:3.0.1'
     implementation 'com.google.code.gson:gson:2.8.5'
     implementation 'com.google.guava:guava:23.0'

examples/redis-backed-cache/build.gradle

@@ -7,7 +7,7 @@ repositories {
 }
 
 dependencies {
-    compileOnly 'org.slf4j:slf4j-api:1.7.25'
+    compileOnly 'org.slf4j:slf4j-api:1.7.26'
     implementation 'redis.clients:jedis:3.0.1'
     implementation 'com.google.code.gson:gson:2.8.5'
     implementation 'com.google.guava:guava:23.0'

examples/singleton-container/build.gradle

@@ -11,7 +11,7 @@ dependencies {
     implementation 'redis.clients:jedis:3.0.1'
     implementation 'com.google.code.gson:gson:2.8.5'
     implementation 'com.google.guava:guava:23.0'
-    compileOnly 'org.slf4j:slf4j-api:1.7.25'
+    compileOnly 'org.slf4j:slf4j-api:1.7.26'
 
     testImplementation 'ch.qos.logback:logback-classic:1.2.3'
     testImplementation 'org.testcontainers:testcontainers'