update carbon.apimgt.version to 6.6.73
update carbon.apimgt.version to 6.6.73

wso2/product-apim,wso2/product-apim,wso2/product-apim,wso2/product-apim,wso2/product-apim,tharikaGitHub/product-apim,tharikaGitHub/product-apim,chamilaadhi/product-apim,tharikaGitHub/product-apim,tharikaGitHub/product-apim,tharikaGitHub/product-apim,chamilaadhi/product-apim,chamilaadhi/product-apim,chamilaadhi/product-apim,chamilaadhi/product-apim