Prevent from including ojdbc8.jar file to gem file
Prevent from including ojdbc8.jar file to gem file

Fix #2163

- Without this change - ojdbc8.jar file is included in the gem file.

```
$ cp /usr/lib/oracle/19.8/client64/lib/ojdbc8.jar lib/.
$ bundle exec rake build
activerecord-oracle_enhanced-adapter 7.0.0.alpha built to pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem.
$ ls -lh pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
-rw-rw-r-- 1 yahonda yahonda 4.0M Apr  1 12:14 pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
cd pkg
$ gem unpack activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
Unpacked gem: '/home/yahonda/src/github.com/rsim/oracle-enhanced/pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha'
$ ls -l activerecord-oracle_enhanced-adapter-7.0.0.alpha/lib/
total 4252
drwxrwxr-x 4 yahonda yahonda    4096 Apr  1 12:14 active_record
-rw-rw-r-- 1 yahonda yahonda     442 Apr  1 12:14 activerecord-oracle_enhanced-adapter.rb
drwxrwxr-x 3 yahonda yahonda    4096 Apr  1 12:14 arel
-rw-r--r-- 1 yahonda yahonda 4340768 Apr  1 12:14 ojdbc8.jar
$
```

- With this change - ojdbc8.jar file is not included in the gem file.

```
$ cp /usr/lib/oracle/19.8/client64/lib/ojdbc8.jar lib/.
$ bundle exec rake build
activerecord-oracle_enhanced-adapter 7.0.0.alpha built to pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem.
$ ls -lh pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
-rw-rw-r-- 1 yahonda yahonda 116K Apr  1 12:22 pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
$ cd pkg
$ gem unpack activerecord-oracle_enhanced-adapter-7.0.0.alpha.gem
Unpacked gem: '/home/yahonda/src/github.com/rsim/oracle-enhanced/pkg/activerecord-oracle_enhanced-adapter-7.0.0.alpha'
$ ls -l activerecord-oracle_enhanced-adapter-7.0.0.alpha/lib/
total 12
drwxrwxr-x 4 yahonda yahonda 4096 Apr  1 12:23 active_record
-rw-rw-r-- 1 yahonda yahonda  442 Apr  1 12:23 activerecord-oracle_enhanced-adapter.rb
drwxrwxr-x 3 yahonda yahonda 4096 Apr  1 12:23 arel
$
```

yahonda/oracle-enhanced,yahonda/oracle-enhanced,rsim/oracle-enhanced,rsim/oracle-enhanced