CI: kafka<=2.3.1 doesn't start (Failed to load SSL keystore)

[ods]

Describe the bug
One of the failing jobs: https://github.com/aio-libs/aiokafka/runs/6469613443?check_suite_focus=true#step:8:1

Relevant part of kafka log:

[2022-06-02 14:33:14,214] ERROR [KafkaServer id=0] Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
org.apache.kafka.common.KafkaException: org.apache.kafka.common.KafkaException: org.apache.kafka.common.KafkaException: Failed to load SSL keystore /ssl_cert/br_server.keystore.jks of type JKS
	at org.apache.kafka.common.network.SslChannelBuilder.configure(SslChannelBuilder.java:73)
	at org.apache.kafka.common.network.ChannelBuilders.create(ChannelBuilders.java:146)
	at org.apache.kafka.common.network.ChannelBuilders.serverChannelBuilder(ChannelBuilders.java:85)
	at kafka.network.Processor.<init>(SocketServer.scala:726)
	at kafka.network.SocketServer.newProcessor(SocketServer.scala:367)
	at kafka.network.SocketServer.$anonfun$addDataPlaneProcessors$1(SocketServer.scala:261)
	at scala.collection.immutable.Range.foreach$mVc$sp(Range.scala:158)
	at kafka.network.SocketServer.addDataPlaneProcessors(SocketServer.scala:260)
	at kafka.network.SocketServer.$anonfun$createDataPlaneAcceptorsAndProcessors$1(SocketServer.scala:223)
	at kafka.network.SocketServer.$anonfun$createDataPlaneAcceptorsAndProcessors$1$adapted(SocketServer.scala:220)
	at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:62)
	at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:55)
	at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:49)
	at kafka.network.SocketServer.createDataPlaneAcceptorsAndProcessors(SocketServer.scala:220)
	at kafka.network.SocketServer.startup(SocketServer.scala:120)
	at kafka.server.KafkaServer.startup(KafkaServer.scala:255)
	at kafka.server.KafkaServerStartable.startup(KafkaServerStartable.scala:38)
	at kafka.Kafka$.main(Kafka.scala:84)
	at kafka.Kafka.main(Kafka.scala)
Caused by: org.apache.kafka.common.KafkaException: org.apache.kafka.common.KafkaException: Failed to load SSL keystore /ssl_cert/br_server.keystore.jks of type JKS
	at org.apache.kafka.common.security.ssl.SslEngineBuilder.createSSLContext(SslEngineBuilder.java:160)
	at org.apache.kafka.common.security.ssl.SslEngineBuilder.<init>(SslEngineBuilder.java:102)
	at org.apache.kafka.common.security.ssl.SslFactory.configure(SslFactory.java:93)
	at org.apache.kafka.common.network.SslChannelBuilder.configure(SslChannelBuilder.java:71)
	... 18 more
Caused by: org.apache.kafka.common.KafkaException: Failed to load SSL keystore /ssl_cert/br_server.keystore.jks of type JKS
	at org.apache.kafka.common.security.ssl.SslEngineBuilder$SecurityStore.load(SslEngineBuilder.java:289)
	at org.apache.kafka.common.security.ssl.SslEngineBuilder.createSSLContext(SslEngineBuilder.java:142)
	... 21 more
Caused by: java.io.IOException: Invalid keystore format
	at sun.security.provider.JavaKeyStore.engineLoad(JavaKeyStore.java:663)
	at sun.security.provider.JavaKeyStore$JKS.engineLoad(JavaKeyStore.java:56)
	at sun.security.provider.KeyStoreDelegator.engineLoad(KeyStoreDelegator.java:224)
	at sun.security.provider.JavaKeyStore$DualFormatJKS.engineLoad(JavaKeyStore.java:70)
	at java.security.KeyStore.load(KeyStore.java:1445)
	at org.apache.kafka.common.security.ssl.SslEngineBuilder$SecurityStore.load(SslEngineBuilder.java:286)
	... 22 more
[2022-06-02 14:33:14,285] INFO [KafkaServer id=0] shutting down (kafka.server.KafkaServer)

Environment (please complete the following information):

• aiokafka version (python -c "import aiokafka; print(aiokafka.__version__)"): master (0.7.0+)
• Kafka Broker version (kafka-topics.sh --version): <= 2.3.1