CI: fix libssh2-devel installation for gpfdist SFTP protocol

libssh2-devel is introduced as a dependency package for the new feature
in the PR #1226.

libssh2-devel is included in rocky-release-hpc, so we need to
rocky-release-hpc before installing libssh2-devel:

```
dnf install rocky-release-hpc
dnf install libssh2-devel
```

Author: tuhaihe

devops/deploy/docker/build/rocky8/Dockerfile

@@ -72,6 +72,7 @@ ENV USER=gpadmin
 RUN dnf makecache && \
     dnf install -y \
         epel-release \
+        rocky-release-hpc \
         git && \
     dnf makecache && \
     dnf config-manager --disable epel && \
@@ -98,6 +99,7 @@ RUN dnf makecache && \
         krb5-devel \
         libcurl-devel \
         libevent-devel \
+        libssh2-devel \
         libuuid-devel \
         libxml2-devel \
         libzstd-devel \

devops/deploy/docker/build/rocky9/Dockerfile

@@ -72,6 +72,7 @@ ENV USER=gpadmin
 RUN dnf makecache && \
     dnf install -y \
         epel-release \
+        rocky-release-hpc \
         git && \
     dnf config-manager --disable epel-cisco-openh264 && \
     dnf makecache && \
@@ -117,6 +118,7 @@ RUN dnf makecache && \
         java-11-openjdk-devel \
         krb5-devel \
         libcurl-devel \
+        libssh2-devel \
         libevent-devel \
         libxml2-devel \
         libuuid-devel \