Bump github.com/uber/jaeger-client-go

Bumps [github.com/uber/jaeger-client-go](https://github.com/uber/jaeger-client-go) from 2.19.0+incompatible to 2.20.0+incompatible.
- [Release notes](https://github.com/uber/jaeger-client-go/releases)
- [Changelog](https://github.com/jaegertracing/jaeger-client-go/blob/master/CHANGELOG.md)
- [Commits](https://github.com/uber/jaeger-client-go/compare/v2.19.0...v2.20.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/uber/jaeger-client-go/config/config_env.go

@@ -52,7 +52,11 @@ const (
 // FromEnv uses environment variables to set the tracer's Configuration
 func FromEnv() (*Configuration, error) {
 	c := &Configuration{}
+	return c.FromEnv()
+}
 
+// FromEnv uses environment variables and overrides existing tracer's Configuration
+func (c *Configuration) FromEnv() (*Configuration, error) {
 	if e := os.Getenv(envServiceName); e != "" {
 		c.ServiceName = e
 	}
@@ -77,13 +81,21 @@ func FromEnv() (*Configuration, error) {
 		c.Tags = parseTags(e)
 	}
 
-	if s, err := samplerConfigFromEnv(); err == nil {
+	if c.Sampler == nil {
+		c.Sampler = &SamplerConfig{}
+	}
+
+	if s, err := c.Sampler.samplerConfigFromEnv(); err == nil {
 		c.Sampler = s
 	} else {
 		return nil, errors.Wrap(err, "cannot obtain sampler config from env")
 	}
 
-	if r, err := reporterConfigFromEnv(); err == nil {
+	if c.Reporter == nil {
+		c.Reporter = &ReporterConfig{}
+	}
+
+	if r, err := c.Reporter.reporterConfigFromEnv(); err == nil {
 		c.Reporter = r
 	} else {
 		return nil, errors.Wrap(err, "cannot obtain reporter config from env")
@@ -93,9 +105,7 @@ func FromEnv() (*Configuration, error) {
 }
 
 // samplerConfigFromEnv creates a new SamplerConfig based on the environment variables
-func samplerConfigFromEnv() (*SamplerConfig, error) {
-	sc := &SamplerConfig{}
-
+func (sc *SamplerConfig) samplerConfigFromEnv() (*SamplerConfig, error) {
 	if e := os.Getenv(envSamplerType); e != "" {
 		sc.Type = e
 	}
@@ -135,9 +145,7 @@ func samplerConfigFromEnv() (*SamplerConfig, error) {
 }
 
 // reporterConfigFromEnv creates a new ReporterConfig based on the environment variables
-func reporterConfigFromEnv() (*ReporterConfig, error) {
-	rc := &ReporterConfig{}
-
+func (rc *ReporterConfig) reporterConfigFromEnv() (*ReporterConfig, error) {
 	if e := os.Getenv(envReporterMaxQueueSize); e != "" {
 		if value, err := strconv.ParseInt(e, 10, 0); err == nil {
 			rc.QueueSize = int(value)